diff --git a/app/abilities/api_ability.rb b/app/abilities/api_ability.rb
index 4ed9708b40..cf84c24c50 100644
--- a/app/abilities/api_ability.rb
+++ b/app/abilities/api_ability.rb
@@ -37,10 +37,10 @@ def initialize(token)
         can [:inbox, :outbox, :read, :update, :destroy], Message if scope?(token, :consume_messages)
         can :create, Message if scope?(token, :send_messages)
 
-        if user.terms_agreed?
-          can [:create, :update, :upload, :close, :subscribe, :unsubscribe], Changeset if scope?(token, :write_api)
-          can :create, ChangesetComment if scope?(token, :write_api)
-          can [:create, :update, :delete], [Node, Way, Relation] if scope?(token, :write_api)
+        if user.terms_agreed? && scope?(token, :write_api)
+          can [:create, :update, :upload, :close, :subscribe, :unsubscribe], Changeset
+          can :create, ChangesetComment
+          can [:create, :update, :delete], [Node, Way, Relation]
         end
 
         if user.moderator?
@@ -48,7 +48,9 @@ def initialize(token)
 
           can :destroy, Note if scope?(token, :write_notes)
 
-          can :redact, [OldNode, OldWay, OldRelation] if user&.terms_agreed? && scope?(token, :write_redactions)
+          can :redact, [OldNode, OldWay, OldRelation] if user.terms_agreed? && scope?(token, :write_redactions)
+
+          can :create, UserBlock if scope?(token, :write_blocks)
         end
       end
     end
diff --git a/app/controllers/api/user_blocks_controller.rb b/app/controllers/api/user_blocks_controller.rb
index 51f0d26d3e..e1fb70a659 100644
--- a/app/controllers/api/user_blocks_controller.rb
+++ b/app/controllers/api/user_blocks_controller.rb
@@ -1,5 +1,8 @@
 module Api
   class UserBlocksController < ApiController
+    before_action :check_api_writable, :only => :create
+    before_action :authorize, :only => :create
+
     authorize_resource
 
     before_action :set_request_formats
@@ -11,5 +14,33 @@ def show
     rescue ActiveRecord::RecordNotFound
       raise OSM::APINotFoundError
     end
+
+    def create
+      raise OSM::APIBadUserInput, "No user was given" unless params[:user]
+
+      user = User.visible.find_by(:id => params[:user])
+      raise OSM::APINotFoundError unless user
+      raise OSM::APIBadUserInput, "No reason was given" unless params[:reason]
+      raise OSM::APIBadUserInput, "No period was given" unless params[:period]
+
+      period = Integer(params[:period], :exception => false)
+      raise OSM::APIBadUserInput, "Period should be a number of hours" unless period
+
+      max_period = UserBlock::PERIODS.max
+      raise OSM::APIBadUserInput, "Period must be between 0 and #{max_period}" if period.negative? || period > max_period
+      raise OSM::APIBadUserInput, "Needs_view must be true if provided" unless params[:needs_view].nil? || params[:needs_view] == "true"
+
+      ends_at = Time.now.utc + period.hours
+      needs_view = params[:needs_view] == "true"
+      @user_block = UserBlock.create(
+        :user => user,
+        :creator => current_user,
+        :reason => params[:reason],
+        :ends_at => ends_at,
+        :deactivates_at => (ends_at unless needs_view),
+        :needs_view => needs_view
+      )
+      render :show
+    end
   end
 end
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 7faf3bebcf..1c26a574f5 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -2663,6 +2663,7 @@ en:
       write_gpx: Upload GPS traces
       write_notes: Modify notes
       write_redactions: Redact map data
+      write_blocks: Create and revoke user blocks
       read_email: Read user email address
       consume_messages: Read, update status and delete user messages
       send_messages: Send private messages to other users
diff --git a/config/routes.rb b/config/routes.rb
index aae32527a4..2ce57404e4 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -112,7 +112,7 @@
       resource :subscription, :only => [:create, :destroy], :controller => "note_subscriptions"
     end
 
-    resources :user_blocks, :only => :show, :id => /\d+/, :controller => "user_blocks"
+    resources :user_blocks, :only => [:show, :create], :id => /\d+/, :controller => "user_blocks"
   end
 
   # Data browsing
diff --git a/lib/oauth.rb b/lib/oauth.rb
index 679c564a63..37393fbf07 100644
--- a/lib/oauth.rb
+++ b/lib/oauth.rb
@@ -1,11 +1,11 @@
 module Oauth
   SCOPES = %w[
     read_prefs write_prefs write_diary
-    write_api read_gpx write_gpx write_notes write_redactions
+    write_api read_gpx write_gpx write_notes write_redactions write_blocks
     consume_messages send_messages openid
   ].freeze
   PRIVILEGED_SCOPES = %w[read_email skip_authorization].freeze
-  MODERATOR_SCOPES = %w[write_redactions].freeze
+  MODERATOR_SCOPES = %w[write_redactions write_blocks].freeze
 
   class Scope
     attr_reader :name
diff --git a/test/controllers/api/user_blocks_controller_test.rb b/test/controllers/api/user_blocks_controller_test.rb
index 169338811d..2705e332d5 100644
--- a/test/controllers/api/user_blocks_controller_test.rb
+++ b/test/controllers/api/user_blocks_controller_test.rb
@@ -3,6 +3,10 @@
 module Api
   class UserBlocksControllerTest < ActionDispatch::IntegrationTest
     def test_routes
+      assert_routing(
+        { :path => "/api/0.6/user_blocks", :method => :post },
+        { :controller => "api/user_blocks", :action => "create" }
+      )
       assert_routing(
         { :path => "/api/0.6/user_blocks/1", :method => :get },
         { :controller => "api/user_blocks", :action => "show", :id => "1" }
@@ -14,11 +18,22 @@ def test_routes
     end
 
     def test_show
-      block = create(:user_block)
+      blocked_user = create(:user)
+      creator_user = create(:moderator_user)
+      block = create(:user_block, :user => blocked_user, :creator => creator_user, :reason => "because running tests")
 
       get api_user_block_path(block)
       assert_response :success
-      assert_select "user_block[id='#{block.id}']", 1
+      assert_select "osm>user_block", 1 do
+        assert_select ">@id", block.id.to_s
+        assert_select ">user", 1
+        assert_select ">user>@uid", blocked_user.id.to_s
+        assert_select ">creator", 1
+        assert_select ">creator>@uid", creator_user.id.to_s
+        assert_select ">revoker", 0
+        assert_select ">reason", 1
+        assert_select ">reason", "because running tests"
+      end
 
       get api_user_block_path(block, :format => "json")
       assert_response :success
@@ -32,5 +47,165 @@ def test_show_not_found
       assert_response :not_found
       assert_equal "text/plain", @response.media_type
     end
+
+    def test_create_no_permission
+      blocked_user = create(:user)
+      assert_empty blocked_user.blocks
+
+      post api_user_blocks_path(:user => blocked_user.id, :reason => "because", :period => 1)
+      assert_response :unauthorized
+      assert_empty blocked_user.blocks
+
+      regular_creator_user = create(:user)
+      auth_header = bearer_authorization_header(regular_creator_user, :scopes => %w[read_prefs])
+      post api_user_blocks_path(:user => blocked_user.id, :reason => "because", :period => 1), :headers => auth_header
+      assert_response :forbidden
+      assert_empty blocked_user.blocks
+
+      auth_header = bearer_authorization_header(regular_creator_user, :scopes => %w[read_prefs write_blocks])
+      post api_user_blocks_path(:user => blocked_user.id, :reason => "because", :period => 1), :headers => auth_header
+      assert_response :forbidden
+      assert_empty blocked_user.blocks
+
+      moderator_creator_user = create(:moderator_user)
+      auth_header = bearer_authorization_header(moderator_creator_user, :scopes => %w[read_prefs])
+      post api_user_blocks_path(:user => blocked_user.id, :reason => "because", :period => 1), :headers => auth_header
+      assert_response :forbidden
+      assert_empty blocked_user.blocks
+    end
+
+    def test_create_invalid_because_no_user
+      blocked_user = create(:user, :deleted)
+      assert_empty blocked_user.blocks
+
+      creator_user = create(:moderator_user)
+      auth_header = bearer_authorization_header(creator_user, :scopes => %w[read_prefs write_blocks])
+      post api_user_blocks_path(:reason => "because", :period => 1), :headers => auth_header
+      assert_response :bad_request
+      assert_equal "text/plain", @response.media_type
+      assert_equal "No user was given", @response.body
+
+      assert_empty blocked_user.blocks
+    end
+
+    def test_create_invalid_because_user_is_unknown
+      creator_user = create(:moderator_user)
+      auth_header = bearer_authorization_header(creator_user, :scopes => %w[read_prefs write_blocks])
+      post api_user_blocks_path(:user => 0, :reason => "because", :period => 1), :headers => auth_header
+      assert_response :not_found
+      assert_equal "text/plain", @response.media_type
+    end
+
+    def test_create_invalid_because_user_is_deleted
+      blocked_user = create(:user, :deleted)
+      assert_empty blocked_user.blocks
+
+      creator_user = create(:moderator_user)
+      auth_header = bearer_authorization_header(creator_user, :scopes => %w[read_prefs write_blocks])
+      post api_user_blocks_path(:user => blocked_user.id, :reason => "because", :period => 1), :headers => auth_header
+      assert_response :not_found
+      assert_equal "text/plain", @response.media_type
+
+      assert_empty blocked_user.blocks
+    end
+
+    def test_create_invalid_because_missing_reason
+      create_with_params_and_assert_bad_request("No reason was given", :period => "10")
+    end
+
+    def test_create_invalid_because_missing_period
+      create_with_params_and_assert_bad_request("No period was given", :reason => "because")
+    end
+
+    def test_create_invalid_because_non_numeric_period
+      create_with_params_and_assert_bad_request("Period should be a number of hours", :reason => "because", :period => "one hour")
+    end
+
+    def test_create_invalid_because_negative_period
+      create_with_params_and_assert_bad_request("Period must be between 0 and #{UserBlock::PERIODS.max}", :reason => "go away", :period => "-1")
+    end
+
+    def test_create_invalid_because_excessive_period
+      create_with_params_and_assert_bad_request("Period must be between 0 and #{UserBlock::PERIODS.max}", :reason => "go away", :period => "10000000")
+    end
+
+    def test_create_invalid_because_unknown_needs_view
+      create_with_params_and_assert_bad_request("Needs_view must be true if provided", :reason => "because", :period => "1", :needs_view => "maybe")
+    end
+
+    def test_create_success
+      blocked_user = create(:user)
+      creator_user = create(:moderator_user)
+
+      assert_empty blocked_user.blocks
+      auth_header = bearer_authorization_header(creator_user, :scopes => %w[read_prefs write_blocks])
+      post api_user_blocks_path(:user => blocked_user.id, :reason => "because", :period => 1), :headers => auth_header
+      assert_response :success
+      assert_equal 1, blocked_user.blocks.length
+
+      block = blocked_user.blocks.take
+      assert_predicate block, :active?
+      assert_equal "because", block.reason
+      assert_equal creator_user, block.creator
+
+      assert_equal "application/xml", @response.media_type
+      assert_select "osm>user_block", 1 do
+        assert_select ">@id", block.id.to_s
+        assert_select ">@needs_view", "false"
+        assert_select ">user", 1
+        assert_select ">user>@uid", blocked_user.id.to_s
+        assert_select ">creator", 1
+        assert_select ">creator>@uid", creator_user.id.to_s
+        assert_select ">revoker", 0
+        assert_select ">reason", 1
+        assert_select ">reason", "because"
+      end
+    end
+
+    def test_create_success_with_needs_view
+      blocked_user = create(:user)
+      creator_user = create(:moderator_user)
+
+      assert_empty blocked_user.blocks
+      auth_header = bearer_authorization_header(creator_user, :scopes => %w[read_prefs write_blocks])
+      post api_user_blocks_path(:user => blocked_user.id, :reason => "because", :period => "1", :needs_view => "true"), :headers => auth_header
+      assert_response :success
+      assert_equal 1, blocked_user.blocks.length
+
+      block = blocked_user.blocks.take
+      assert_predicate block, :active?
+      assert_equal "because", block.reason
+      assert_equal creator_user, block.creator
+
+      assert_equal "application/xml", @response.media_type
+      assert_select "osm>user_block", 1 do
+        assert_select ">@id", block.id.to_s
+        assert_select ">@needs_view", "true"
+        assert_select ">user", 1
+        assert_select ">user>@uid", blocked_user.id.to_s
+        assert_select ">creator", 1
+        assert_select ">creator>@uid", creator_user.id.to_s
+        assert_select ">revoker", 0
+        assert_select ">reason", 1
+        assert_select ">reason", "because"
+      end
+    end
+
+    private
+
+    def create_with_params_and_assert_bad_request(message, **params)
+      blocked_user = create(:user)
+      assert_empty blocked_user.blocks
+
+      moderator_creator_user = create(:moderator_user)
+      auth_header = bearer_authorization_header(moderator_creator_user, :scopes => %w[read_prefs write_blocks])
+
+      post api_user_blocks_path({ :user => blocked_user.id }.merge(params)), :headers => auth_header
+      assert_response :bad_request
+      assert_equal "text/plain", @response.media_type
+      assert_equal message, @response.body
+
+      assert_empty blocked_user.blocks
+    end
   end
 end