STORY: A torrent of water burst through the massive dam on the river that separates Russian and Ukrainian forces in southern Ukraine on Tuesday, flooding a large swathe of the war zone and forcing villagers to flee, prompting finger-pointing from both sides.

As a result, about 42,000 people were at risk from flooding in Russian- and Ukrainian-controlled areas along the Dnipro River, as the U.N. aid chief warned of grave and far-reaching consequences.

Ukraine said Russia had committed a deliberate war crime in blowing up the Soviet-era dam, which powered a hydroelectric station. The Kremlin blamed Ukraine, saying it was trying to distract from the launch of a major counteroffensive Moscow says is faltering.