After prior attempts to evacuate civilians were thwarted by ceasefire violations, the Ukrainian port city of Mariupol, which is besieged by Russian soldiers, said it will resume efforts on Sunday.

“The evacuation of the civilian population will begin at 1200 (1000 GMT),” city officials said in a statement, adding that a truce has been reached with Russian-led forces around the city.

An previous attempt on Saturday to let civilians to depart by bus and private automobile along the road northwest towards Zaporizhzhia was thwarted when both sides claimed the other was shelling.

Doctors Without Borders (MSF) describes the humanitarian situation in Mariupol, a main target for Russian invading forces, as “catastrophic,” with civilian dwellings lacking power and water.

Laurent Ligozat, MSF’s emergency coordinator in Ukraine, told AFP that “it is important that this humanitarian corridor… be put in place very rapidly.”

Ukrainian authorities say the Russians shelled the city even as citizens gathered to organize an escape convoy, but Moscow’s defense ministry says the city’s defenders are using a “human shield.”

Separately, the director of the Kyiv-controlled Lugansk regional government announced on Sunday that a train would be planned to evacuate Lysychansk’s women, children, and the elderly.

Lysychansk is on the forefront of a battle between Ukrainian forces and rebels backed by Russia, who are seeking to join up with Russian forces and take control of the entire southeast.

“You must travel alone to Lysychansk station. “First, ladies with children, then women under 40, women, and the elderly,” Sergiy Gaiday posted on Telegram.

Russian forces will dominate Ukraine’s whole Azov Sea coast if they capture Mariupol, which held out against rebel forces during the previous 2014 conflict.

If they decide to advance north in an attempt to conquer all of eastern Ukraine, this would provide them with a landbridge from Russia to Russian-annexed Crimea, as well as a key supply route and port.