DONETSK, Ukraine — Heavy fighting broke out in the center of the main rebel holdout of Donetsk as government forces and pro-Russia militia exchanged artillery and tank fire, further complicating efforts to remove bodies from the Malaysia Airlines Flight MH17 crash site.
Rebels closed off roads and moved men and weaponry around the main railway station in Donetsk, the provincial capital, with heavy shelling audible in the distance. Local authorities urged residents to stay at home, and streets around the station were mostly deserted.
Rebel tanks were filmed driving toward the location of the shelling.
A rebel driver named Vladimir, who said he lived in the area, told BuzzFeed that Ukrainians began an offensive early in the morning, opening fire from tanks and Grad missile launchers. Smoke could be seen rising from near the central market. Eyewitnesses said a nine-story building was on fire. Passengers were evacuated from the train station area at 9.30 a.m.
Pro-Kiev news site Ukrainska Pravda reported seeing the bodies of four civilians at a school near the train station.
Local website 62.ua reported seeing another civilian dead at a supermarket in the area.
Shell casings could be seen lying around the residential neighborhood.
The fighting looked certain to complicate efforts to retrieve the bodies of the 298 plane crash victims. Ukraine says 282 of the bodies have been recovered and that 251 of them are awaiting transfer to cold storage in train wagons in the town of Torez south of the main crash site in Hrabove, about 50 miles east of Donetsk. Three Dutch forensic investigators arrived in Donetsk earlier on Monday, with a further 31 international experts in Kharkiv, a Ukrainian-controlled city 185 miles to the north, to where the government wants to send the bodies.
A rebel leader, Andriy Purgin, told the Interfax news service that pro-Russia separatist groups would organize for the bodies to be sent to the eastern city of Kharkiv.
"So far the victims' bodies remain in the railcars of the refrigerator train at the Torez station. They will be sent to Kharkiv only after international experts — Dutch, Malaysian, or the Red Cross representatives — arrive at the scene. They are to accompany the train with the bodies, we are ready to add a separate railcar for them," he said.
It was not clear who started Monday's fighting, which has worrying implications for both sides as attempts to remove the bodies and bring in international experts dragged on for a fifth day. Rebels, under heavy criticism for a shambolic cleanup operation, said that Ukraine opened fire first.
Ukraine's security council said that its forces were "not responsible" for the explosions and under strict orders not to use artillery or airstrikes in the city. President Petro Poroshenko ordered Ukrainian forces to refrain from combat operations within a 40-kilometer radius of the crash site.
But a Ukraine military spokesman told the Washington Post that it was "a planned offensive": The military is trying to push rebels away from the airport, said Vladislav Seleznev. "Aviation and artillery are not aiming at civilian residences," he said. "Their only aim is to block the terrorists and fighters."
Security council spokesman Andriy Lysenko suggested that the fighting involved one of the numerous loosely organized pro-Kiev irregular groups. Many of the volunteer battalions are made up of nationalist protesters from the country's west and often act independently of Kiev's central command.
"There is work on clearing approaches to the city, on destroying terrorist checkpoints. If there are explosions in the middle of the city, this is not Ukrainian soldiers," Lysenko told reporters. "If there is fighting in the city, we have information that there is a small self-organized group that are fighting with the terrorists."