Moscow decries US move to allow its weapons to be used on targets in Russia

Senior officials say decision marks a serious escalation and that the threat to use tactical nuclear weapons is not a bluff

The Kremlin has said Joe Biden's decision to allow Ukraine to use US-supplied weapons against targets in Russia demonstrates Washington's deep involvement in the conflict, as some of Vladimir Putin's allies increased their nuclear threats against the west.

The Kremlin spokesperson Dmitry Peskov told journalists on Friday that Moscow was already aware of attempts by Ukraine to strike targets on Russian territory with weapons provided by the US.