Russian attacks killed four people in Ukraine overnight, as Moscow and Kyiv await the arrival of U.S. envoys to begin a new push for peace in the Kremlin's 4 1/2-year-old invasion.

The planned visit by Steve Witkoff and Jared Kushner, who is also U.S. President Donald Trump's son-in-law, is hoped to revive peace talks amid escalating aerial attacks by both sides.

The last known visit to Moscow by Witkoff and Kushner, was in January, when they met Russian President Vladimir Putin in the Kremlin.