US President Joe Biden called on Russian President Vladimir Putin on Tuesday to reduce tensions stirred by a Russian military build-up on Ukraine’s border and proposed a summit of the estranged leaders to tackle a raft of disputes.

The White House and the Kremlin reported only the second conversation between the two since Biden took office in January, after Western officials urged Moscow to end the build-up and Russia, in words recalling the Cold War, said its “adversary” should keep US warships well away from the Crimea region.