Russian forces kept up their bombardment of the port city of Mariupol on Thursday, while satellite photos showed that a massive convoy that had been mired outside the Ukrainian capital split up and fanned out into towns and forests near Kyiv, with artillery pieces moved into firing positions, Associated Press reported.

International condemnation escalated over an airstrike in Mariupol a day earlier that killed three people at a maternity hospital. Western and Ukrainian officials called the attack a war crime. Ukrainian President Volodymyr Zelenskyy said the Russian refusal to permit evacuations from the port city amounted to “outright terror.”

Meanwhile, the highest-level talks held since the invasion began two weeks ago yielded no progress, the number of refugees fleeing the country topped 2.3 million, and Kyiv braced for an onslaught, its mayor boasting that the capital had become practically a fortress protected by armed civilians.

Satellite imagery from Maxar Technologies showed that 40-mile (64-kilometer) convoy of vehicles, tanks and artillery has broken up and been redeployed, the company said. Armored units were seen in towns near the Antonov Airport north of the city. Some of the vehicles have moved into forests, Maxar reported, with towed howitzers nearby in position to open fire,  according to the Associated Press.

The convoy had massed outside the city early last week, but its advance appeared to have stalled amid reports of food and fuel shortages. U.S. officials said Ukrainian troops also targeted the convoy with anti-tank missiles.

A U.S. defense official speaking on condition of anonymity said some vehicles were seen moving off the road into the tree line in recent days, but the official could not confirm whether the convoy had dispersed.

In Mariupol, a southern seaport of 430,000, the situation was increasingly dire as civilians trapped inside the city scrounged for food and fuel. More than 1,300 people have died in the 10-day siege of the frigid city, said Deputy Prime Minister Iryna Vereshchuk.

Residents have no heat or phone service, and many have no electricity. Nighttime temperatures are regularly below freezing, and daytime ones normally hover just above it. Bodies are being buried in mass graves. The streets are littered with burned-out cars, broken glass and splintered trees, Associated Press reported.

“They have a clear order to hold Mariupol hostage, to mock it, to constantly bomb and shell it,” Zelenskyy said in his nightly video address to the nation. He said the Russians began a tank attack right where there was supposed to be a humanitarian corridor.