Russian armed forces are creating a “security buffer zone” along the border between Russia and Ukraine, President Vladimir Putin said Thursday.

CHERNIHIV REGION, Ukraine (AP) — An exchange of prisoners between Russia and Ukraine from their more than three-year war was underway Friday, a senior Ukrainian official said. The swap was not yet finished, according to the official, who spoke on condition of anonymity because he was not authorized to speak publicly.

Russian authorities have been forced to shut down airports in Moscow amid a barrage of Ukrainian drone strikes overnight, Russian officials and state media reported on May 23. Operations have been suspended at Moscow's Vnukovo,