A satellite image shows destroyed grocery stores and shopping malls, amid Russia's ongoing invasion of Ukraine, in Mariupol, Ukraine, March 9, 2022.  Satellite image ©2022 Maxar Technologies/Handout via REUTERS    ATTENTION EDITORS - THIS IMAGE HAS BEEN
A satellite image shows destroyed grocery stores and shopping malls, amid Russia's ongoing invasion of Ukraine, in Mariupol, Ukraine, March 9, 2022. Satellite image ©2022 Maxar Technologies/Handout via REUTERS ATTENTION EDITORS - THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. Reuters / MAXAR TECHNOLOGIES

Russian shelling of Mariupol on Thursday prevented a humanitarian convoy reaching the besieged Ukrainian city, local officials said, and dented hopes of evacuating trapped civilians who are increasingly desperate for supplies.

Residents have been cowering under fire, and without power or water, in the Black Sea port city of over 400,000 people for more than a week and attempts to arrange a local ceasefire and safe passage out have failed repeatedly.

Another "humanitarian corridor" appeared to have failed on Thursday, a day after the bombing of a hospital in the city which President Volodoymr Zelenskiy said had killed two adults and a child.

"Bombs are hitting houses," the Mariupol city council said in an online post released as the top Ukrainian and Russian diplomats held talks in Turkey. The council said a university and a theatre had also been hit but gave no casualty figures.

Russia, which invaded Ukraine on Feb. 24, denies targeting civilians.

Petro Andrushenko, an adviser to the mayor of Mariupol, told Reuters that Russian aircraft were targeting the routes that humanitarian aid was trying to use to enter the city, and along which buses were being prepared to evacuate people.

"We try and try and try, but I'm not sure if it'll be possible today - or other days," he said by phone.

"Airstrikes started from the early morning. Airstrike after airstrike. All the historic centre is under bombardment."

The bombardment, he said, had continued "without any gaps, without any pause", hitting houses and buildings along the evacuation routes.

"They want to absolutely delete our city, delete our people. They want to stop any evacuation," he said.

"SPECIAL OPERATION"

Russia calls its military actions in Ukraine a "special operation" that it says is not designed to occupy territory but to destroy its neighbour's military capabilities and capture what it regards as dangerous nationalists.

Presidential adviser Oleksiy Arestovych said Russia was deliberately preventing the evacuation of civilians because it had failed to seize the strategically important city.

Zelenskiy accused Russia of carrying out genocide after officials said Russian aircraft had bombed the hospital in Mariupol, burying patients in rubble despite a local ceasefire deal.

Kremlin spokesman Dmitry Peskov said on Wednesday that Russian forces "do not fire on civilian targets" and said on Thursday that Moscow would look into the incident. Other Russian officials rejected what they said was "fake news, with one saying the hospital had been taken over by Ukrainian troops.

Zelenskiy said in a televised address: "Like always, they lie confidently."