Baghdad, Iraq ? An armed vigilante group threatened on Tuesday to kill Abu Musab al-Zarqawi for insurgency attacks that have killed Iraqis, making the first internal threat against the Jordanian militant.

Insurgents detonated a car bomb that killed 14 Iraqis, underscoring their determination to carry out attacks a week after the U.S. transferred power to an interim government led by Prime Minister Iyad Allawi.

The car bomb in the town of Khalis tore through a tent packed with hundreds of Iraqis mourning a man killed in an assassination attempt of a local official by insurgents days earlier.

The blast left a yard-wide crater, set five cars on fire and burned the tent. Dismembered corpses lay on the floor. White plastic chairs where mourners had been sitting in orderly rows were broken and twisted.

Elsewhere, seven U.S. Marines assigned to the 1st Marine Expeditionary Force were killed in western Iraq, the military said. Two died in action Monday, while a third died of his wounds Monday. Four other Marines were killed Tuesday while conducting security and stability operations.

Allawi — a longtime CIA ally with ties to former military chiefs from Saddam Hussein’s regime — has said security is his top priority, and his government is expected today to announce a new law that will expand security forces’ powers and allow the imposition of curfews.

The emergence of the vigilante group potentially brings a new element into the Iraqi insurgency, highlighting internal opposition to al-Zarqawi, who is believed to have links to al-Qaida.

In a videotape sent to Al-Arabiya television, the previously unknown group, which called itself the “Salvation Movement,” ordered al-Zarqawi to leave the country and questioned how he could justify the killing of civilians and his threats to assassinate Allawi.

One gunman, seated behind a table reading a statement, questioned how al-Zarqawi could use Islam to justify assassinations, kidnappings and the killings of innocents.

An Iraqi security officer stands at the scene of a car bomb that exploded in Khalis, Iraq, northeast of Baghdad. Fourteen people who were attending a wake for the victims of a previous attack were killed in Tuesday's blast.

“He must leave Iraq immediately, he and his followers and everyone who gives shelter to him and his criminal actions,” he said, speaking in an Iraqi accent.

“We swear to Allah that we have started preparing … to capture him and his allies or kill them and present them as gift to our people,” he said. “This is the last warning. If you don’t stop, we will do to you what the coalition forces have failed to do.”