Haider Abadi, who was named prime minister late Monday, promised to create a more inclusive government to work with the international community in the fight against Islamic State "to stop the spread of this cancer."
The militant Sunni gunmen who have proclaimed a fundamentalist Muslim caliphate in the Iraqi and Syrian territory they have seized were able to roll over much of northern Iraq this past spring with little resistance from the Sunni populations marginalized and neglected by the Shiite-dominated government of former Prime Minister Nouri Maliki.
President Obama had made a deeper U.S. commitment to the fight against the militants contingent on Iraqis forming a government that addresses the needs of the country's Kurdish and Sunni communities. Obama planned to lay out his strategy for the fight against Islamic State in an address to the nation Wednesday night.
Kerry hailed what he said was a promise made by Abadi to reform Iraq's government and military and take on the fight against Islamic State, which is also often referred to as ISIL, its original name as the Islamic State in Iraq and the Levant.
Kerry said Abadi told him the new government is committed to "bring every segment of Iraqi society to the table."
Kerry arrived in Baghdad on Wednesday at the start of a Middle East tour to drum up political, military and financial support for an international coalition to confront the threat to the region posed by Islamic State, which has massacred hundreds in its campaign of terror against anyone opposed to its extremist actions and medieval religious tenets.
"We all have an interest in supporting the new government of Iraq," Kerry said after his meeting with Abadi. "The coalition that is at the heart of our global strategy I assure you will continue to grow and deepen in the days ahead."
He said the United States and its allies "will simply not stand by to watch as ISIL's evil spreads."
French Foreign Minister Laurent Fabius also pledged his country's readiness to take part in airstrikes against the extremists if needed.
France is already providing weapons to Kurdish forces fighting Islamic State's advance in northern Iraq.
At a later meeting with Iraqi President Fuad Masum, Kerry was told the timing of his visit was crucial in supporting efforts to broaden the government and get Iraq's Sunni minority engaged in the battle against the violent extremists of their sect.
"As the president made clear, there was no way that this strategy could be implemented without the government formation taking place," Kerry told Masum, according to a State Department transcript of their comments to journalists in Baghdad.
Kerry said Americans were gratified by the Iraqi parliament's endorsement of a new slate of ministers but made clear that the work to reform the Baghdad leadership was still a work in progress. He said he looked forward to helping the new leaders to "fulfill the full promise of a national reform program."
The State Department announced during Kerry's visit to Baghdad that it was providing an additional $48 million in humanitarian aid to Iraq to help the hundreds of thousands displaced by Islamic State's advance, which has included seizure of Iraq's second-largest city, Mosul.