"The members of the Security Council expressed their full support of sovereignty and territorial integrity of Ukraine," the Security Council said in statement. "The members of the Security Council called for an immediate return to a ceasefire regime."

The Security Council includes both Russia and the Ukraine, which is a rotating member of the council. Both nations had agreed to the Security Council statement, which noted the unrest's "severe impact on the local civilian population".

Earlier in the day, Ukraine and Russia had blamed each other for a surge in fighting in recent days that has led to the highest casualty toll in weeks and cut off power and water to thousands of civilians on the front line.

The Ukrainian military and Russian-backed separatists accuse each other of launching offensives in the government-held industrial town of Avdiyivka and firing heavy artillery in defiance of the two-year-old Minsk ceasefire deal.

Eight Ukrainian troops have been killed and 26 wounded since fighting intensified on Sunday - the heaviest losses for the military since mid-December, according to government figures.