The US has deployed 50 troops to an air base in Iraq's troubled Anbar province to help in the fight against Islamic State (IS).

A Pentagon spokesperson said the military advisers would examine site facilities and support Iraqi forces.

The deployment is the first time US troops have been sent to Anbar since US air strikes against IS began in August.

US forces left Iraq in 2011, but President Barack Obama last week he was sending 1,500 as advisors.

Anbar, now largely under the control of Islamic State jihadsts, was previously a base for al-Qaeda in Iraq and a hotbed of resistance to US forces during the years after 2003.

A spokesperson for the US military's Central Command told Reuters news agency the 50 troops would be stationed at the Ain al-Asad air base, the largest in Anbar.

Colonel Patrick Ryder added that though the troops were operating in an advisory capacity, they would defend themselves if attacked.

"A portion of the group consists of force protection personnel and any weapons US forces possess are for force protection requirements," he said.