Ukrainian police had to fire warning shots into the air to stop a convoy near the town of Kramatorsk in Donetsk region after these vehicles had earlier forced their way through a Sloviansk checkpoint and injured police officers.

The convoy was spotted near Kramatorsk at about 22:00 local time on Tuesday, the Donetsk regional police department said. The convoy ignored the demand that the vehicles stop, and a police officer had to fire a number of warning shots into the air to make the convoy comply and protect the law enforcement officials' lives and health, it said.

"It appeared that the same group of individuals had forced their way into the Anti-Terrorist Operation zone. It included parliamentarian Volodymyr Parasiuk, who, according to an earlier statement, was supposed to be at a hospital at the time," the report said.

An investigative team of the Kramatorsk police department was sent to the scene. An inquiry is underway.

Previously, the Donetsk regional police reported the opening of a criminal case on the counts of 'a threat or violence against a law enforcement officer' following a brawl at a checkpoint near Sloviansk.

Yuriy Holuban, the commander of a special-operations police company of Donetsk region, said a convoy carrying unknown individuals had approached the checkpoint at about 19:00 on Tuesday. The people were told that they had to cross the roadblock consistent with the ATO headquarters' regulations, i.e. to produce their IDs and to prepare their vehicles for inspection.

"These people refused to do so. MP Parasiuk alighted and started threatening and insulting the police officers with foul language and tried to provoke a brawl. He failed to achieve the goal on his own and gave an order to his companions from the convoy. In fact, citizen Parasiuk led an attack on the police officers," Holuban said.

About 40-45 people were involved in the attack, the report said.

Holuban said he had decided not to use firearms against the assailants. Seven police officers, including five from the special-operations company and two from the Sloviansk police department, were hurt in the conflict.

"An officer of the special-operations company was hit by the parliament deputy's car; he is in hospital. Two officers sustained injuries, and another two were sprayed with pepper gas and suffered severe facial burns," Holuban said.

The Donetsk regional police asked the Ukrainian Prosecutor's Office to appraise parliamentarian Parasiuk's conduct, insisting that he led the attack on the police at the checkpoint near Sloviansk.