Baghdad:Iraqi tribesmen battled militants from the Islamic State group in their Fallujah stronghold for a second day Saturday a significant challenge to long-running jihadist control of the city officials said.

Fallujah is one of two Iraqi cities still controlled by IS but residents -- said to number in the tens of thousands -- vastly outnumber the estimated 300 to 400 jihadists inside it.

But IS has had plenty of time to assert its control over the civilian population and discourage dissent via arrests and executions.

"Armed confrontations between the sons of the Fallujah tribes and the Daesh organisation are continuing" an army brigadier general said using an Arabic acronym for IS.

The clashes are taking place in Al-Jolan in northwest Fallujah and Nazal in the centre the officer said adding that the army was shelling IS positions on the outskirts.

There have been casualties among both the tribesmen and the jihadists the officer said without giving a number.

Tribal leader Sheikh Majeed al-Juraisi said that fighting was continuing in both the centre and north of Fallujah.

The tribesmen "are beginning to run out of supplies and need the support of the government" he added.

There is "fear that they will completely run out and afterwards the Daesh organisation will arrest and massacre them."

Seeking government support

In 2014 and 2015 IS executed dozens of members of the Albu Nimr tribe which opposed the jihadists' seizure of most of Anbar province including Fallujah.

Saadun Obaid al-Shaalan who was elected by a local council to administer the Fallujah area confirmed that the fighting was ongoing saying that tribesmen had posted snipers on rooftops in the Al-Askari area of east Fallujah.

He said the tribesmen were in need of help and "we are trying to obtain that support" from the government.

Officials said the clashes began on Friday as a fight between tribesmen and Al-Hisba IS members charged with enforcing religious strictures in the city.

Members of the Al-Juraisat Al-Mahamda and Al-Halabsa tribes joined the fighting as it escalated.

Fallujah which lies about 50 kilometres (30 miles) west of Baghdad is the only Iraqi city apart from IS's main northern hub Mosul still under jihadist control.

Anti-government fighters took control of the city in early 2014 during unrest that broke out after security forces demolished a protest camp farther west and it became a key IS stronghold.

Several large town in the north are also held by the jihadists including Tal Afar and Hawijah.

IS launched a sweeping offensive that overran swathes of northern and western Iraq in June 2014 but security forces and allied fighters have pushed the jihadists back with support from US-led air strikes.

Tribesmen have played a key role in holding the jihadists back in several areas including Haditha in Anbar Amerli in Salaheddin province and Dhuluiyah in Diyala.

And Sunni Arab tribesmen from Anbar province helped drive back IS's predecessor organisation Al-Qaeda in Iraq after joining forces with US troops from 2006.

AFP