Ukrainian security forces on Friday retook control of an industrial city in the country's east that had been held by separatists, a top official in the government said.
Troops swept into Mariupol in the restive Donetsk region about 4:50 a.m. and battled the militants for several hours, dismantling checkpoints and barricades, overrunning sniper positions and destroying an armored vehicle, Ukrainian Interior Minister Arsen Avakov said on his Facebook account.
He cited "high losses" among the militants and two wounded among Ukrainian troops.
"It is a pity that Mariupol was awakened by gunshots, but the city of steelmakers must not live and work as dictated by terrorists," Avakov wrote. "The situation in the city is stable. A Ukrainian national flag was hoisted over the Mariupol city council."
His account could not be immediately verified by independent sources.
Mariupol became the first major city in the region to be retaken from separatist gunmen in two months of on-and-off fighting that began after protests drove pro-Russia President Viktor Yanukovich from power in February. Eastern Ukraine has a large Russian-speaking population that includes separatists opposed to the new central government in Kiev, the capital.
Later in the day, newly elected President Petro Poroshenko ordered the regional authorities to set up their temporary headquarters in Mariupol, given that the city of Donetsk, the regional capital, remains largely controlled by pro-Russia gunmen.
"Thanks to the heroism of Ukraine's military the situation in Mariupol has stabilized," Poroshenko said in a statement posted on the presidential website.
Mariupol appeared deserted most of the day, with its shops, offices and businesses closed, a witness said.
"We knew something was going on when the [pro-Russia] self-defense militants were very actively fortifying their barricades in town and installing large-caliber machine guns on some roofs and at some intersections the night before," Andrei Klochenok, a 37-year-old resident and steelworker, said in a telephone interview. "The shooting in the morning was so intense that my wife and I were afraid to even approach the windows, which were shaking with explosions outside."
His two children were evacuated last week to stay with friends in Kiev.
"I hope that is the end of the war in our town," Klochenok said.
About 30 separatists were detained during the operation, Anton Gerashchenko, an aide to Avakov, said at a briefing in Kiev.
"One of Mariupol terrorist commanders code named Boroda [Beard] was found in a basement and warned that if he didn't come out a hand grenade would be thrown down there," he said. "That is why the leader gave himself up."
In Washington, meanwhile, a U.S. State Department spokeswoman confirmed a report from Ukrainian officials this week that tanks had crossed into their territory from Russia.
"In the last three days a convoy of three T-64 tanks, several BM-21 or Grad multiple rocket launchers and other military vehicles crossed from Russia into Ukraine near the Ukrainian town of Snizhne," said spokeswoman Marie Harf. "This is unacceptable."
The operation in Mariupol could mark a turning point for confronting separatists in the Donetsk and Luhansk regions, defense expert Yuri Butusov said.
"Our power structures finally got their act together and proved to be capable of conducting a large-scale military operation, kicking the terrorists out of a strategic town with minimal casualties," Butusov, editor of Tsenzor.net, a popular Ukrainian online journal, said in a telephone interview. The militants, he said, are losing support because the region's residents "have grown immensely sick and tired of lawlessness and terrorism imported from Russia."
However, government operations against the rebels suffered a setback Friday in another area of Donetsk close to the Ukrainian border with Russia. An airborne brigade from the city of Mykolayev ran into an ambush and sustained heavy casualties, an online publication reported. Two soldiers were killed and 25 were wounded, the report by Ukrainskaya Pravda said.
Summing up the day of fighting, defense expert Dmitry Tymchuk reported on his Facebook page that Ukrainian forces destroyed two of three Russian tanks that had crossed into Ukraine the day before. The militants also lost three armored vehicles, two trucks and two utility vehicles with large-caliber machine guns mounted on the them, Tymchuk wrote.
Four Ukrainian soldiers were killed and 31 wounded, he said.
Elsewhere, Denis Pushilin, a separatist leader of the self-proclaimed Donetsk People's Republic, narrowly escaped death Thursday night when his minibus exploded in the city of Donetsk, killing two aides and wounding seven other people, according to a statement posted Friday on the separatist group's official website.