The Islamic State has reportedly burned 45 people to death in the newly captured western Iraqi town of al-Baghdadi in Iraq's Anbar province.

According to the BBC, al-Baghdadi's police chief Col Qasim al-Obeidi said that the latest victims of the Islamic State's executions possibly included captured members of the Iraqi security forces who fought against the militants during the attack.

The report cannot be confirmed because of the fighting and the "poor communications" in the area, the BBC said.

The IS militants had seized the town on Thursday, ending the months-long siege of the area. According to Reuters, the militants launched multiple attacks on al-Baghdadi from two directions before making a major push into the town centre. 

"Ninety per cent of al-Baghdadi district has fallen under the control of the insurgents," district manager Naji Arak said in an interview with Reuters over the phone on Thursday.

Al-Baghdadi is only five kilometers northwest of Ain al-Asad, where 320 US Marines are conducting training for Iraq's 7th Division. Fox News reported that a group of about 20-25 ISIS fighters, including suicide bombers, tried to storm Ain al-Asad on Friday but were repelled by the air base's Iraqi guards before they could break through. US Apache helicopters were also deployed to assist, but Iraqi ground forces were able to eliminate the threat before they arrived. 

Rear Admiral John Kirby told CNN on Saturday that the attack "at least got to the outer base limits" but took place "several kilometers" away from where the US Marines were situated.

"We're still looking at this and it's hard to say whether they breached the perimeter or not. But they certainly got to the perimeter level at the very least," Kirby said.

The Pentagon spokesman said that the US forces were at a distance from where the break-in was attempted, but there was "no question that they're close to danger."