This was stated by Vadym Skibitskyi, a representative of the Defence Intelligence of Ukraine, in an interview for The New York Times.

These missiles were part of weaponry that Ukraine handed over to Russia in the 1990s under an international agreement aimed at assuring Ukraine’s sovereignty and territorial integrity. All ballistic missiles, Tu-160 and Tu-95 strategic bombers were also handed over. Now, they are using Kh-55 missiles against us with these bombers.

According to Vadym Skibitskyi, among the missiles that terrorist country is using against Ukraine’s civilian objects are, in particular, Kh-55 subsonic cruise missiles designed in the 1970s to carry a nuclear warhead. The warhead had been removed by russians and ballast added to disguise the fact that it was not carrying a payload.