BAGHDAD - Former insurgents wearing masks and wailing in grief joined a funeral procession yesterday honoring a Sunni Muslim leader killed for turning his guns on Islamic extremists rather than Americans.

The burial of Naseer Salam al-Maamouri, 29, served as a show of resolve for Iraqi tribes that have chosen to back the U.S.-led struggle to regain control of Baqubah, the strategic urban hub of Diyala province northeast of Baghdad.

For the moment, the tribal militias have given U.S. and Iraqi forces a key advantage in seeking to clear extremist-held pockets in and around Baghdad. But the Sunni militiamen are demanding something in return: permanent jobs and influence in Iraq's security forces.

The Shiite-led government has been slow to respond, despite Washington's fears that the tribal support could collapse without swift integration into the standing forces.

Shiite cleric Abdul-Aziz al-Hakim, head of Iraq's biggest Shiite party, the Supreme Islamic Iraq Council, delivered a mixed message about the Sunni groups yesterday.

"I want to remind people about the role that our police and army forces are playing," he told about 5,000 faithful during a sermon in southwest Baghdad. ". . . They are practicing an honorable national role, they are expressing the unity of Iraqis in confronting the enemies of Iraq."

But Hakim tempered his praise with a warning that the tribal fighters must remain "on the side of the government in chasing terrorists and criminals."

He said they should be active only in areas where there is sustained fighting. He said they should stand down in less volatile areas for fear they will stir up sectarian strife.

The outreach to Sunnis and the cries of mourning at the funeral were both telling signs of how far Iraq has changed in the last year. Last year, many of today's pro-American Sunni groups were fighting U.S. troops, and the Pentagon worried openly about a Shiite-Sunni civil war.

This month, the U.S. military reported a 60 percent decline in violence since June.

At the funeral yesterday, masked gunmen placed an Iraqi flag on Maamouri's casket and loaded it onto a pickup truck. AP Television News footage showed trucks taking the casket for burial.

Maamouri was one of the local security chiefs of the 1920s Revolution Brigades. He was driving in Baqubah with two bodyguards, handing out gifts for the Eid al-Adha festival, when he was kidnapped and later killed.