A second attempt to evacuate civilians from a southern Ukrainian port city where supplies are running short was stopped due to a Russian assault, a Ukrainian official said.
The planned evacuations in Mariupol through humanitarian corridors were halted because of an ongoing assault, interior ministry adviser Anton Gerashchenko said.
"There can be no ‘green corridors’ because only the sick brain of the Russians decides when to start shooting and at whom," Gerashchenko wrote on Telegram.
Russian and Ukrainian forces had agreed to a cease-fire to allow civilians to be evacuated from the port city where food and medicine are in short supply. There have been increasing calls for humanitarian corridors to allow civilians to escape as the death toll rises.
The UN human rights office said on Sunday that 364 Ukrainian civilians have died since the beginning of the Russian invasion and a further 759 people have been injured.
Around 1.5 million Ukrainians have fled the country in the same amount of time, as a refugee crisis develops on the EU's border.
Pavlo Kirilenko, governor of the Donetsk Oblast region said on Facebook that people in Vuglehdar and Berdyansk would be left without gas "as the occupiers have damaged the Donetsk Mariupol main line."
He also said that Russian shelling on a residential building in Kramatorsk, north of Mariupol, has resulted in "at least two casualties."
However, Russian President Vladimir Putin blamed the Ukrainian side, stating that the "pause in hostilities was again used only to build up forces and means in (Ukrainian) positions", according to the Kremlin's readout of Putin's call with French President Emmanuel Macron.
Meanwhile, officials in northeastern Ukraine said on Sunday morning that they were waiting to evacuate civilians as fights were waged in Kharkiv.
"We are waiting for the opening of the so-called "green corridors" to evacuate the population and deliver humanitarian goods. Organisationally, we are completely ready," said Oleg Sinegubov, head of the Kharkiv regional state administration.
He also said that "every day about 30,000 people leave Kharkiv railway station to safe places."
Ukraine's President Volodymyr Zelenskyy issued a new appeal for a no-fly zone over Ukraine after a Russian missile strike on an airport in Vinnitsya.
While Russian forces have advanced in Ukraine, they have met fierce resistance. Ukrainian authorities said on Sunday that since the beginning of the conflict, some 11,000 Russian troops have lost their lives.
In its daily intelligence assessment, the UK ministry of defence said Russia was targeting populated areas such as Kharkiv and Mariupol to break Ukrainian morale. It said that Russia has been surprised by "the scale and strength of Ukrainian resistance" and slowed down by Ukraine targeting its supply lines.