The United States and its allies will destroy Russian troops and equipment in Ukraine and sink its Black Sea fleet  if Russian President Vladimir Putin uses nuclear weapons in his war against Ukraine, former CIA Director General David Petraeus said on Monday. 

He noted that he had spoken to National Security Adviser Jake Sullivan about a possible US response to Russian nuclear escalation, with the administration officials saying to have been repeatedly communicating to Moscow.

Asked whether Russia's use of nuclear weapons in Ukraine would lead to the involvement of the US. and NATO in the war, Petraeus said that it would not be a situation that would trigger the alliance's Article 5, which calls for collective defense.

The former official said that if radiation reaches any of the NATO member states, it would be perceived as an attack on the alliance.