US Secretary of State John Kerry has met the new Iraqi PM at the start of a Middle East tour to build support for action against Islamic State (IS).
Haidar al-Abadi formed a unity government less than 48 hours ago.
An inclusive government was a condition for greater US and Nato support in the fight against IS militants who have taken over large parts of the country.
US President Barack Obama is due to outline his plans to combat IS on Wednesday evening.
He said on Tuesday that he had authority to widen military action against IS without the approval of Congress, but said he would still ask lawmakers to endorse the arming of Syrian opposition forces.
IS militants have taken over large parts of Syria and Iraq in recent months and have declared a “caliphate”.
The US has already conducted dozens of airstrikes on IS targets in the past month, in an effort to protect ethnic and religious minorities threatened by IS.
IS militants described the beheadings of two US journalists as a retaliation against the strikes.
Saudis ‘main target’
Mr Kerry’s regional visit will continue in Saudi Arabia and other regional capitals, where he is hoping to boost military, political and financial support for the fight against IS.
Iraqi MPs approved members of Mr Abadi’s new cabinet on Monday, paving the way for the creation of a new government.
The US had insisted on the formation of an administration which did more to address the grievances of the Sunni and Kurdish minorities to allow the creation of a united front against IS.
The previous mostly Shia government of Nouri Maliki was considered to be too narrowly sectarian.
But despite US interest in Iraq’s internal affairs, a senior state department official told the BBC that Mr Kerry will mostly talk to leaders here about Baghdad’s role in the global coalition.