(CN) — Russian troops appeared to be closing in on the capture of the key southern port city of Mariupol on Thursday and pounded Ukrainian positions in other parts of the country.
In Mariupol, Ukrainian officials said they had pulled more than 130 people from out of the wreckage of the Drama Theater, which was struck Wednesday. Hundreds of people were reportedly hunkering down in the theater's basements to avoid shelling.
It remained unclear if anyone was killed in the blast, but city officials said more than 1,000 people may have been in the building and that rescue efforts were slow due to the total breakdown of city services.
The blast at the theater came a week after Russia was accused of shelling a maternity hospital in Mariupol with pregnant mothers and medical staff inside.
Alleged intentional attacks on civilians prompted U.S. President Joe Biden to call Russian President Vladimir Putin a “war criminal” for the first time on Wednesday, setting up a major hurdle for diplomatic efforts. He doubled down on Thursday at a St. Patrick’s Day event where he called Putin a “murderous dictator, a pure thug who is waging an immoral war against the people of Ukraine.”
Mariupol has been the scene of horrific fighting between Russian and pro-Russian Ukrainian forces against hardcore Ukrainian fighters with the Azov Regiment. Fighting has reached the city center as Russian forces move in to seize the city, according to military sources.
A city with about 400,000 residents, Mariupol is in the midst of a humanitarian catastrophe, though tens of thousands of traumatized civilians have been able to leave in cars and on foot in the past few days. Videos posted online show a city destroyed by war.
Ukraine alleged a Russian warplane bombed the theater while Russia accused Azov fighters of detonating explosives inside it. As of Thursday, it had not been independently verified how the building was blown up.
Wednesday saw hopes for a ceasefire and even a peace deal grow with both sides saying they were making progress in negotiations. But harsher fighting and rhetoric quickly returned on Thursday.
“Negotiations are complicated. The positions of the parties are different. For us, fundamental issues are inviolable,” said Mykhailo Podoliak, a top adviser to Ukrainian President Volodymyr Zelenskyy, on Twitter.
It seems Ukraine may be unwilling to grant autonomous status to two eastern Ukrainian regions that Russia has recognized as independent and not want to legitimize Russia’s annexation of Crimea in 2014.
With negotiations on a ceasefire mired in difficulties, the war seems far from over.
On Thursday, there were reports of deadly shelling by Russian forces in many key cities and towns, including Chernihiv, a city north of Kyiv, in Kharkiv, Ukraine’s second-largest city, on the outskirts of Kyiv, the capital, and in eastern Ukraine where fighting has been very intense. About 60,000 Ukrainian troops are believed to be engaged in bitter battle in eastern Ukraine and Russian forces are trying to encircle them.

Ukraine reported some counterattacks too and presented new evidence of successful attacks on Russian tanks, armored vehicles and aircraft.
On Thursday, Western intelligence sources told media outlets, including the New York Times, that they estimated that more than 7,000 Russian soldiers have been killed and that up to 21,000 have been wounded in three weeks of fighting. These numbers, though, cannot be independently verified and may be exaggerated to give a sense that Russia is on the verge of defeat.