Russia summons US envoy in protest after four killed in a Ukrainian missile strike on Crimea

The Russian foreign ministry has summoned the US Ambassador, saying Washington has direct responsibility for an attack on Russian-annexed Crimea.

Four people were killed by falling debris in Sevastopol on Sunday.
Russia says it shot down five Ukrainian missiles over the port city.
Moscow says US specialists helped oversee the flight path of those missiles.
A Pentagon spokesperson said Ukraine conducts its own military operations.