An attack on an Iranian police convoy Saturday in the country’s restive southern province of Sistan and Baluchestan killed at least 10 officers, local authorities said.

The attack took place in Gohar Kuh, some 1,200 kilometers (745 miles) southeast of the Iranian capital, Tehran.

HalVash, an advocacy group for the Baluch people of Afghanistan, Iran and Pakistan, posted photos and video of the aftermath of the attack, including a damaged police vehicle and corpses in another vehicle that was attacked. no explosives appeared to have been used.

IRNA reported that an investigation had been launched. Baluch nationalists have been carrying out low-level insurgencies in that region, crossing the borders of three countries, for several years. Thus far, however, no suspects have been arrested or claimed responsibility for the attack.