Russian forces pressed their assault on Ukrainian cities Friday, with new missile strikes and shelling on the capital Kyiv and the outskirts of the western city of Lviv, as world leaders pushed for an investigation of the Kremlin’s repeated attacks on civilian targets, including schools, hospitals and residential areas.

The early morning barrage of missiles on the outskirts of Lviv was the closest strike yet to the center of the city, which has become a crossroads for people fleeing from other parts of Ukraine and for others entering to deliver aid or fight.

Black smoke billowed for hours after the explosions, which hit a facility for repairing military aircraft near the city’s international airport, only six kilometers (four miles) from the center. One person was wounded, the regional governor, Maksym Kozytskyy, said.

Multiple blasts hit in quick succession around 6 a.m., shaking nearby buildings, witnesses said. The missiles were launched from the Black Sea, but the Ukrainian air force’s western command said it had shot down two of six missile in the volley. A bus repair facility was also damaged, Lviv’s mayor Andriy Sadovyi said.