...Relations are deteriorating as local fighters negotiate to avoid a U.S.-led military offensive against Fallujah, while foreign fighters press to attack Americans and their Iraqi supporters. The disputes have spilled over into harsh words and sporadic violence, with Fallujans killing at least five foreign Arabs in recent weeks, according to witnesses.

"If the Arabs will not leave willingly, we will make them leave by force," said Jamal Adnan, a taxi driver who left his house in Fallujah's Shurta neighborhood a month ago after the house next door was bombed by U.S. aircraft targeting foreign insurgents...

...U.S. and Iraqi authorities together have insisted that if Fallujah is to avoid an all-out assault aimed at regaining control of the city, foreign fighters must be ejected. Several local leaders of the insurgency say they, too, want to expel the foreigners, whom they scorn as terrorists. They heap particular contempt on Abu Musab Zarqawi, the Jordanian whose Monotheism and Jihad group has asserted responsibility for many of the deadliest attacks across Iraq, including videotaped beheadings.

"He is mentally deranged, has distorted the image of the resistance and defamed it. I believe his end is near," Abu Abdalla Dulaimy, military commander of the First Army of Mohammad, said recently.

One of the foreign guerrillas killed by local fighters was Abu Abdallah Suri, a Syrian and a prominent member of Zarqawi's group, whose body was discovered Sunday. Suri was shot in the head and chest while being chased by a carload of tribesmen, according to a security guard who said he witnessed the killing...