I am going to write a paragraph about an international disaster. But I have no idea which choice is proper / fixed / better sounding in this context:
The previous Saturday the United Nations Human Rights Council strongly condemned X for its .......... attacks on civilians, in a resolution that was stronger in criticism than the one passed by the Security Council on the same day. By a majority vote the Council asked X to immediately stop its attacks.
According to the dictionary definitions:
Brutal = cruel, violent, and completely without feelings
Savage = extremely violent, wild, or frightening
Merciless = having or showing no mercy
As you see, these definitions are so close that a leaner like me can fall into doubt about how he/she should make a distinction between them and find a direct equivalent in their mother language(s).
That was why I decided to bring it up here to ask you for your opinions.
PS. I see no difference between "brutal" and "merciless", but "savage" has a slightly more violence / harshness involved in my mind, which I cannot explain. However, You are free to dispute it.