diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index 94f435948..94c63a6be 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -229,9 +229,14 @@ class ApplicationController < ActionController::Base
         format.any(:atom, :pdf, :csv) {
           redirect_to signin_path(:back_url => url)
         }
-        format.xml  { head :unauthorized, 'WWW-Authenticate' => 'Basic realm="Redmine API"' }
+        format.api  {
+          if Setting.rest_api_enabled? && accept_api_auth?
+            head(:unauthorized, 'WWW-Authenticate' => 'Basic realm="Redmine API"')
+          else
+            head(:forbidden)
+          end
+        }
         format.js   { head :unauthorized, 'WWW-Authenticate' => 'Basic realm="Redmine API"' }
-        format.json { head :unauthorized, 'WWW-Authenticate' => 'Basic realm="Redmine API"' }
         format.any  { head :unauthorized }
       end
       return false
diff --git a/test/integration/api_test/disabled_rest_api_test.rb b/test/integration/api_test/disabled_rest_api_test.rb
index f0283ba34..cefa82499 100644
--- a/test/integration/api_test/disabled_rest_api_test.rb
+++ b/test/integration/api_test/disabled_rest_api_test.rb
@@ -41,11 +41,11 @@ class Redmine::ApiTest::DisabledRestApiTest < Redmine::ApiTest::Base
     @token = Token.create!(:user => @user, :action => 'api')
 
     get "/news.xml?key=#{@token.value}"
-    assert_response :unauthorized
+    assert_response :forbidden
     assert_equal User.anonymous, User.current
 
     get "/news.json?key=#{@token.value}"
-    assert_response :unauthorized
+    assert_response :forbidden
     assert_equal User.anonymous, User.current
   end
 
@@ -55,11 +55,25 @@ class Redmine::ApiTest::DisabledRestApiTest < Redmine::ApiTest::Base
     end
 
     get "/news.xml", :headers => credentials(@user.login, 'my_password')
-    assert_response :unauthorized
+    assert_response :forbidden
     assert_equal User.anonymous, User.current
 
     get "/news.json", :headers => credentials(@user.login, 'my_password')
-    assert_response :unauthorized
+    assert_response :forbidden
+    assert_equal User.anonymous, User.current
+  end
+
+  def test_with_valid_username_and_wrong_password_http_authentication
+    @user = User.generate! do |user|
+      user.password = 'my_password'
+    end
+
+    get '/news.xml', :headers => credentials(@user.login, 'wrong_password')
+    assert_response :forbidden
+    assert_equal User.anonymous, User.current
+
+    get "/news.json", :headers => credentials(@user.login, 'wrong_password')
+    assert_response :forbidden
     assert_equal User.anonymous, User.current
   end
 
@@ -68,11 +82,11 @@ class Redmine::ApiTest::DisabledRestApiTest < Redmine::ApiTest::Base
     @token = Token.create!(:user => @user, :action => 'api')
 
     get "/news.xml", :headers => credentials(@token.value, 'X')
-    assert_response :unauthorized
+    assert_response :forbidden
     assert_equal User.anonymous, User.current
 
     get "/news.json", :headers => credentials(@token.value, 'X')
-    assert_response :unauthorized
+    assert_response :forbidden
     assert_equal User.anonymous, User.current
   end
 end