People take cover from shelling inside an entryway to an apartment building in Mariupol, Ukraine, on March 13. (Evgeniy Maloletka/AP)Around 350,000 people are still trapped in Mariupol, the city in southeastern Ukraine that has been besieged by Russian troops since March 1, a local official said.”Considering there are 540,000 residents and around 150,000 people evacuated in the first three days when it was still safe to do so, we estimate around 350,000 people to be stuck in Mariupol,” Petro Andriushchenko, adviser to the Mariupol mayor, said on Ukrainian television Monday.Multiple official attempts to establish safe corridors and evacuate civilians from Mariupol have failed in recent days. A large convoy of humanitarian aid that was meant to arrive on Sunday has still not reached the city as of Monday, according to officials.”Most of the people are staying in the basements and shelters in inhumane conditions. With no food, no water, no electricity, no heating,” he said, adding that people were melting snow and dismantling the heating system to get water to drink.Speaking about civilian casualties, Andriushchenko said the numbers obtained from the police and compiled by medical facilities were likely inaccurate. He said that, as of Sunday, 1,800 people were confirmed to have been killed.Speaking on Monday, Oleksiy Arestovych, an adviser in President Volodymyr Zelensky’s office, said that the Russian bombardment of Mariupol has caused more than 2,500 deaths.