MARIUPOL, Ukraine — Ukrainian security forces driving armored vehicles attacked a police station in this city of half a million Friday, reducing the building to smoldering rubble and killing at least seven people, according to local residents who said they had seen the assault.
The attack signaled what appeared to be a major escalation in the interim government's fight with pro-Russian militants in southeastern Ukraine, and it came two days after President Vladimir Putin of Russia urged that the separatists delay a referendum scheduled for Sunday and that all sides settle their differences through dialogue.
Hours after the assault, the bodies of two of the dead were still lying in the street, possibly victims of gunfire that the security forces leveled against a crowd of people who broke away from a pro-Russian Victory Day march to lend support to the police inside the station, residents said.
The death toll was expected to rise as rescue workers gained access to the police station, which exploded in flames during the attack. Hospital officials said they were treating 26 people for wounds and holding the bodies of five others.
In recent weeks, Ukrainian army units have set up bases outside many of the cities in southeastern Ukraine where pro-Russian militants have seized public buildings and proclaimed an independent Donetsk People's Republic. In that time, the units attacked a few rebel-held checkpoints, but until Friday they had not undertaken a frontal assault on any of the buildings being held by the separatists.
Unlike in other parts of eastern Ukraine, the security forces in Mariupol seemed determined not to cede control of the city without a fight. The heavily armed forces arrived about 10 a.m. and fought a fierce two-hour battle to retake the building.
By afternoon, the police station was a smoldering ruin. A plume of smoke rose into the sky where the roof had collapsed. The walls were charred and pockmarked with bullet holes, and there were at least three large cavities apparently caused by heavy weapons.
Information from the Washington Post was used in this report.