Regional heavyweight Saudi Arabia is to host talks Thursday between Kerry and ministers from 10 Arab states plus Turkey on joint action against the Islamic State group.
The moves came as Britain announced it was shipping $2.6 million (two million euros) worth of weapons to Kurdish forces fighting the jihadists in Iraq.
Kerry's expected arrival in the region tomorrow comes with Washington buoyed by the formation of a new government in Baghdad.
Iraq's campaign to claw back the territory it lost in the Sunni Arab heartland north and west of Baghdad in June -- and US efforts to engage Sunni governments in the fightback -- have been complicated by sectarian politics in the region.
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Saudi Arabia and the five other Gulf Arab states had deeply strained relations with the Shiite-led government in Baghdad, with each side blaming the other for the jihadists' advance.
They will address "terrorism in the region, extremist organisations behind it and means of fighting them," Saudi state media said.
The Arab League, which has stopped short of explicitly backing ongoing US air strikes against IS, also drummed up regional support for the fight.
Nabil al-Arabi, the head of the pan-Arab bloc, on Tuesday "affirmed the necessity of rallying regional and international efforts to bolster Iraq in this critical phase."
"Almost every single country has a role to play in eliminating the (IS) threat and the evil that it represents," he said.
Notably absent from Jeddah will be the Syrian government -- facing a three-and-a-half-year uprising backed by many of the participants -- and its regional ally Iran.