The United States and Russia bitterly attacked each other over the Ukraine crisis in a diplomatic brawl Monday at the U.N. Security Council, in a session replete with acidic exchanges that could have been lifted from the Cold War era.

The Americans, backed by their Western allies, accused Russia of endangering peace and destabilizing global security by massing more than 100,000 troops on Ukraine’s borders, while Kremlin diplomats dismissed what they called baseless and hysterical U.S. fear-mongering aimed at weakening Russia and provoking armed conflict.

"The situation we are facing in Europe is urgent and dangerous,” U.S. Ambassador Linda Thomas-Greenfield said in her opening remarks to a televised meeting of the Council that Russia had sought to prevent. "Russia’s actions strike at the very heart of the U.N. charter.”