diff --git a/docs/api/api/api.txt b/docs/api/api/api.txt
index 94b4267ee6a..cfd3bb2a926 100644
--- a/docs/api/api/api.txt
+++ b/docs/api/api/api.txt
@@ -1014,9 +1014,9 @@ GET /comments/package/:project/:pname
 
 XmlResult: directory
 
-POST /comments/request/:id
-POST /comments/project/:name
-POST /comments/package/:project/:pname
+POST /comments/request/:id?parent_id=<parent_comment_id>
+POST /comments/project/:name?parent_id=<parent_comment_id>
+POST /comments/package/:project/:pname?parent_id=<parent_comment_id>
 
   Create a comment for the object
 
diff --git a/src/api/app/controllers/comments_controller.rb b/src/api/app/controllers/comments_controller.rb
index b9af9ad897f..8a58d6d37de 100644
--- a/src/api/app/controllers/comments_controller.rb
+++ b/src/api/app/controllers/comments_controller.rb
@@ -7,7 +7,7 @@ def show_comments
   end
 
   def create
-    @obj.comments.create!(body: request.raw_post, user: User.current)
+    @obj.comments.create!(body: request.raw_post, user: User.current, parent_id: params[:parent_id])
     render_ok
   end
 
diff --git a/src/api/app/models/comment.rb b/src/api/app/models/comment.rb
index b0f8f7c0600..bab09ee00be 100644
--- a/src/api/app/models/comment.rb
+++ b/src/api/app/models/comment.rb
@@ -7,6 +7,8 @@ class Comment < ApplicationRecord
 
   validates :body, :commentable, :user, presence: true
 
+  validate :validate_parent_id
+
   after_create :create_notification
   after_destroy :delete_parent_if_unused
 
@@ -88,4 +90,10 @@ def destroy
   def delete_parent_if_unused
     parent.destroy if parent && parent.user == User.find_nobody! && parent.children.length.zero?
   end
+
+  def validate_parent_id
+    return unless parent_id
+    return if commentable.comments.where(id: parent_id).present?
+    errors.add(:parent, "belongs to different object")
+  end
 end
diff --git a/src/api/spec/models/comment_spec.rb b/src/api/spec/models/comment_spec.rb
index 5d3aa26f681..6c989850610 100644
--- a/src/api/spec/models/comment_spec.rb
+++ b/src/api/spec/models/comment_spec.rb
@@ -2,9 +2,9 @@
 
 RSpec.describe Comment do
   let(:comment_package) { create(:comment_package) }
-  let(:comment_package_with_parent) { create(:comment_package, parent: comment_package) }
-  let(:comment_package_with_parent_2) { create(:comment_package, parent: comment_package) }
-  let(:comment_package_with_grandparent) { create(:comment_package, parent: comment_package_with_parent) }
+  let(:comment_package_with_parent) { create(:comment_package, parent: comment_package, commentable: comment_package.commentable) }
+  let(:comment_package_with_parent_2) { create(:comment_package, parent: comment_package, commentable: comment_package.commentable) }
+  let(:comment_package_with_grandparent) { create(:comment_package, parent: comment_package_with_parent, commentable: comment_package.commentable) }
 
   describe "has a valid Factory" do
     it { expect(comment_package).to be_valid }
@@ -21,6 +21,10 @@
     it { is_expected.to validate_presence_of(:body) }
     it { is_expected.to validate_presence_of(:commentable) }
     it { is_expected.to validate_presence_of(:user) }
+    it {
+      expect { create(:comment_package, parent: comment_package) }.to raise_error(
+        ActiveRecord::RecordInvalid, "Validation failed: Parent belongs to different object")
+    }
   end
 
   describe "to_xml" do