Baghdad, Nov 2 (IANS): The Islamic State (IS) militant group Sunday executed 67 tribesmen in Iraq's western province of Anbar, a security source said.

The incident took place in the early hours of Sunday when the militants captured families of the Albu Nimer tribe in a rural area while they were fleeing their village, some 200 km from Baghdad, the source told Xinhua.

The militants executed 67 men of the captured families, accusing them of being part of the government-backed Sahwa paramilitary groups.

Earlier, IS militants executed 255 tribesmen from the same tribe.

Security forces and their allied Sunni tribesmen of Albu Nimer have been battling the extremist Sunni militants since mid-October.

They managed to hold parts of Heet area, preventing it from falling into the hands of the IS which has taken control of most of the town.

The IS has seized around 80 percent of Iraq's largest province of Anbar and is trying to advance toward Baghdad, but many counter attacks by security forces and Shia militia have pushed them away.