In Ukraine’s south, Russian forces seize or encircle cities in steady advance

And in Odessa, a major port city on the Black Sea, the mayor said in videos that it was preparing for its defense amid unverified reports that a large fleet of Russian warships was heading toward the waters off the city’s coast. “Who are you saving us from,” the mayor, Gennady Trukhanov, said in a video posted online, using an expletive, in comments directed at Russian forces who claimed to be saving ethnic Russians and Russian-language communities in Ukraine.

“Our job today is to act so that every meter of our Odessa land is under control of us, Odessians,” he told reporters.

Russia claims control of vital port city in Ukraine, as convoy outside Kyiv remains stalled

Farther north, Russian forces have unleashed a barrage of air and artillery assaults on urban centers. The capital city of Kyiv and Ukraine’s second-largest city, Kharkiv, as well as the northern city of Chernihiv, have all come under fierce attack but remain in Ukrainian hands, according to local officials and assessments from Britain, which defense analysts say has substantial intelligence capabilities in the region.

A large explosion lit up the night sky in Kyiv in the early hours of Thursday, local time, according to video footage verified by The Washington Post.

The blast, which was captured by a camera in the city’s southeastern neighborhoods, took place in a region to the west of Kyiv, apparently striking an area far from the city center. Between late Wednesday night and Thursday morning, air raid sirens have sounded at least six times, urging residents to take shelter, according to messages in the official municipal government Telegram channel.

Britain’s Ministry of Defense said Thursday morning that a massive convoy of Russian troops and tanks poised north of the Ukrainian capital remains more than 18 miles away from Kyiv’s center. The ministry said delays stemmed in part from “Ukrainian resistance, mechanical breakdown and congestions,” with the column having made “little discernible progress over three days.”

The line of armored vehicles, tanks and towed artillery had been wending its way closer to Kyiv, drawing within 20 miles of the city center on Monday, satellite images showed. The fleet stretched for some 40 miles, according to U.S. firm Maxar Technologies, which captured the photos Monday.

Ukrainian and U.S. officials have described Russian forces as bogged down in many parts of the country, facing fuel and food shortages, apart from the substantial advances in the south. “They have lost a sense of momentum,” Pentagon spokesman John Kirby said Wednesday. But U.S. officials have cautioned that Moscow probably would bounce back from early setbacks and continued to maintain the upper hand against Ukraine’s outgunned and less-experienced military.

The Russian government Wednesday said 498 service members have died in the Ukraine war and 1,597 have been wounded, conceding for the first time the high death toll of just a week’s fighting. There was no way to verify the toll, and Russian officials often understate casualty figures. Defense Ministry spokesman Igor Konashenkov said 572 service members have been captured.

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The mayor of Mariupol said Thursday that the southern coastal city — a strategic location whose capture could allow Russia to create a land bridge from southern Russia to Crimea, which Moscow controls — was still under Ukrainian control.

“They impede the supply of food, create a blockade for us,” Vadym Boychenko, said in a Telegram post from the city council. He said people could not leave because of the damage to trains and bridges.

Mariupol was still under Ukrainian control but Russian troops had encircled it, the deputy mayor, Sergei Orlov, said in a television interview. “The situation is quite critical,” he said, adding that it was difficult to estimate how many people had been killed in hours of shelling and air raids because it was impossible to collect all the bodies.

The mayor, Boychenko, added Thursday morning that his team was trying to secure a safe corridor to bring in supplies or help evacuate residents. “We again have no light, water and heat,” he said. “We are doing everything to restore the critical infrastructure of the city as soon as possible.”

Over a crackling phone line, Petro Andryuschenko, an adviser to the Mariupol mayor’s office, said that the port city was completely surrounded. “There’s no electricity, no heating. We haven’t got water,” he said. That’s because Russia has bombed all critical infrastructure, he said. Three water towers have been targeted as well as electricity substations. He said that at least 10 people had been killed in the past two days with at least 150 injured in the city’s one functioning hospital, but city officials have no reliable estimate of the true toll.

“The last day and a half they’ve been bombing all the time, we can’t even go outside to assess.” The working hospital has electricity from a back up generator, he said, but he’s not sure how long fuel supplies will last. He said the Greek consulate had managed to organize the evacuation of some of its diplomats Wednesday. Communications are largely cut. “There are some points in the city where we have a weak connection,” he said, before the line dropped.

The most easterly side of the city is in ruins, he reported. “A region with 150,000 people completely bombed,” he said.

Ukrainian President Volodymyr Zelensky on Thursday said that 16,000 foreigners have volunteered to fight for Ukraine against the Russian invasion.

In an emotional video posted to his Telegram channel, Zelensky referenced the “international legion” of foreign volunteers he sought to defend Ukraine. Earlier this week, Ukraine temporarily lifted visa requirements for foreign volunteers who wish to enter the country and join the fight against Russian forces.

More than 1 million people have fled Ukraine since Russia’s invasion, seeking safety in neighboring countries like Poland, Hungary, Romania, Slovakia and Moldova.

Fahim reported from Istanbul, Morris from Vinnytsia, Ukraine, and Francis from London.