BAGHDAD (AP) — Iraqi authorities on Thursday found the bodies of 48 Sunni tribesmen killed by the Islamic State group in the restive western province of Anbar, an official said.

Faleh al-Issawi, a councilman in the Anbar provincial government, said the bodies were found in a mass grave outside the town of Hit. Those killed were tribal fighters allied with the government and members of the security forces who were rounded up from villages around Hit after IS militants seized the area in early October, he said.

It was the second such mass grave uncovered in as many days. A grave found Wednesday contained bodies of 30 Sunni fighters killed hours earlier. They too had been captured during the fall of Hit, a town located about 140 kilometers (85 miles) west of Baghdad.

Most of the tribal fighters came from the Al Bu Nimr tribe, he said.

"The government should help Al Bu Nimr to fight back. The situation is tragic and civilians are leaving their houses fearing more reprisals from the IS group," al-Issawi said.

The IS militants have seized large swaths of land in western and northern Iraq in the country's worst crisis since the 2011 U.S. troop withdrawal.