Russian Foreign Minister Sergei Lavrov warned there’s a “serious” danger of nuclear conflict, as U.S. Defense Secretary Lloyd Austin said Washington’s goal was to see Russia weakened so it can’t attempt a repeat of the war.

President Joe Biden named a career diplomat to be the U.S.’s new ambassador to Ukraine as his administration ramped up its military aid and diplomatic presence in the country that has been fighting invading Russian forces for about two months.