"On Wednesday, along the Upper Kurchaloi-Belgaty highway in the Vedeno District, unidentified attackers opened fire using automatic weapons and grenade launchers on a 13-vehicle police convoy returning to base following a security operation," the source said.
Three high-ranking police officers and the head of the Vedeno District administration were hit in the crossfire, he said.
"The wounded received medical attention, the site has been sealed off, and a search is now underway for the perpetrators," the source said.
He added that three police cars were badly damaged in the assault.
Another police source said an armed group was discovered in a forest five kilometers (three miles) from the village of Khal-Kiloi, in the Shatoi District.
"The militants resisted arrest, and one of them was killed in the ensuing exchange of gunfire," the source said. "His identity is being established, and a search is underway for the rest of the group."
