US Secretary of State John Kerry held talks with Iraq's new leaders Wednesday on their role in a long-awaited strategy against Islamic State jihadists to be unveiled by President Barack Obama.
Iraq has been at the centre of US efforts to halt IS since its fighters spearheaded a lightning offensive in June seizing much of the Sunni Arab heartland north and west of Baghdad.
But in a keenly awaited policy speech later Wednesday, Obama was widely expected to announce the expansion of the month-old US air campaign to neighbouring Syria, where IS has seized a swathe of the northeast, bordering Iraq.
The US administration has come under mounting domestic and international criticism for not taking stronger action against IS fighters who have committed a spate of atrocities in recent weeks, many of them paraded on the Internet.
Kerry's unannounced talks in Baghdad were the first stop on a regional tour to build support for the new US strategy which he has said will only work with the backing of the "broadest possible coalition of partners around the globe."
He was to fly on to Saudi Arabia for talks on Thursday with 11 regional foreign ministers on a joint campaign against IS.
US efforts to build a broad regional coalition had been complicated by the sectarian politics of the region, with Saudi Arabia and other Sunni states deeply suspicious of the Shiite-led government in Baghdad.
But they were given a boost on Monday by the formation of a new government that Kerry has said has "the potential to unite all of Iraq's diverse communities".
Kerry met new Prime Minister Haidar al-Abadi, a Shiite regarded as far less divisive than his predecessor Nuri al-Maliki, who was criticised for driving many in the Sunni minority into the arms of IS.
US officials have hailed a more constructive approach from Abadi to recapturing Sunni Arab areas from the jihadists after the heavy-handed security tactics of Maliki's government.
Kerry praised the new premier's "commitment to the broad reforms that are necessary in Iraq to bring every segment of the Iraqi society to the table."
He welcomed the "military's commitment to reconstituting itself" for the fightback.
But the scale of the security challenge facing Iraq was underlined by twin bombs that killed at least seven people in east Baghdad during Kerry's visit.
- Locally recruited fightback -
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Much of the regular army is drawn from Iraq's Shiite majority who come from Baghdad and the south and are despised outsiders in Sunni areas.
US officials have welcomed the new government's acceptance that Sunnis need to take charge of the fightback against IS in Sunni areas.
"Abadi has said repeatedly since he was named the prime minister that he is not going to... take military units from the south and go into areas in the north and west to take on (IS)" a US official told journalists travelling with Kerry.
Instead national guard units "grown from the provinces... locally recruited," will take the "primary security responsibility" for the fightback in the five provinces where IS fighters hold sway in Sunni areas.
The official stressed that the new units would need to be "paid by national funds," which was one of the areas where Baghdad would need the international help that Kerry intends to discuss with regional governments in Saudi Arabia on Thursday.
"The region and our partners in the Gulf can play a really important role... in terms of their encouragement, in terms of their financial contributions, in terms of lifting the burden that the government here has.
"Even for a country that’s still exporting about 2.6 million barrels of oil a day, the financial toll of the crisis is quite staggering," the official said.
- Syria air strikes? -
In his speech later on Wednesday, Obama was expected to steel Americans for a prolonged battle against the jihadists, despite devoting much of his presidency to avoiding new entanglements in the Middle East.
But wary of repeating what he believes were the mistakes of the last decade, Obama was expected to renew his pledge not to send ground troops back to Iraq.
Both the New York Times and the Washington Post said Obama was preparing to authorise the expansion of the air campaign against IS that he launched in Iraq on August 8 to neighbouring Syria.
An opinion poll published on Tuesday suggested 65 percent of Americans would approve such an expansion of air strikes, which would be without the authorisation of the Damascus government.
But Brussels-based think-tank the International Crisis Group (ICG) warned "the resulting boost to IS recruitment might outweigh the group's tactical losses."
Washington has pinned its hopes of pegging back IS in Syria on rebel groups opposed to the jihadists, baulking at cooperation of any sort with the regime of President Bashar al-Assad whose overthrow it has supported since 2011.
However the main anti-jihadist rebel alliance suffered a major blow late Tuesday when a blast in the northwest killed 47 of its top commanders.