BAGHDAD: U.S. Vice President Mike Pence Saturday assured Iraqi Prime Minister Haider al-Abadi of continued U.S. support to defeat ISIS, the Iraqi government said in a statement.

The two discussed the situation in Syria and the war on ISIS in a phone call from Pence following Friday's U.S. strikes on a Syrian airbase to punish a chemical attack that killed scores of civilians this week in an area held by the opposition to Syrian President Bashar al-Assad.

Pence "affirmed that U.S. policy in the region didn't change, its priority is to defeat Daesh (ISIS) in Iraq and the region," said a statement from Abadi's office.

The Shi'ite-led Iraqi government issued a statement Friday in reaction to the events in Syria reflecting a difficult balancing act between its alliance with the United States and with Shi'ite Iran, a key backer of Assad.

The Iraqi statement condemned the chemical attack, without naming Assad, calling instead for an international investigation to identify the perpetrator.

The statement also criticized "the hasty interventions" that followed the chemical attack, in an apparent reference to the U.S. strikes.

A U.S.-led coalition has been providing air and ground support to Iraqi forces battling the militants, allowing them to recapture most cities they had overran in 2014 in Sunni areas of northern and western Iraq.

An Iranian-backed Iraqi Shi'ite militia said Friday it would keep on fighting in Syria in support of Assad, despite the U.S. missile strikes.

"Our movement is proceeding on the path of jihad and resistance, and our position concerning the war in Syria won't change," al-Nujaba spokesman Hashim al-Musawi said in a statement.

Al-Nujaba is one of the groups accused by human rights organisations of killing scores of fleeing civilians in the Syrian city of Aleppo last year.

Iran, by leveraging its ties with Iraq's Shiites, has emerged as the main power broker in Iraq after the United States withdrew its troops in 2011.