Putin mentions possible use of nuclear weapons again

Russian President Vladimir Putin has frequently talked about using nuclear weapons in recent years, and he's done so again at an economic forum in St. Petersburg.

Putin was responding to a moderator's questions on Friday after delivering a speech.

He said nuclear weapons could be used if Russia's sovereignty and territorial integrity come under threat.

He added that he does not think such a scenario has occurred, but does not rule out changing the country's nuclear doctrine.

Washington recently gave Ukraine permission to use US-made weapons for limited strikes on Russian territory. In St. Petersburg, Putin said his country reserves the right to supply long-range weapons to adversaries of the West.

In his speech, Putin said Russia remains a key part of global trade, and maintains economic ties with friendly nations despite all obstacles and sanctions.