Senior officials from the U.S. and Russia meet in Saudi Arabia on improving ties and ending the war in Ukraine - but Ukraine isn't invited.

Talks between the United States and Russia over the war in Ukraine are set to begin Tuesday, multiple sources have told CNN.

Saudi Arabia's crown prince wasn't in the room for the first high-level talks between Russia and the United States over Moscow's war on Ukraine on Tuesday, but Mohammed bin Salman still won the day for hosting the gathering that could be a game-changer in the bloody conflict.