FALLUJAH, Iraq Oct 12 (AFP) - US forces hammered rebel positions in Iraq`s Sunni Muslim hotbeds of Fallujah and Ramadi Tuesday, killing 11 people, as the disarming of Shiite militiamen gathered pace in Baghdad despite US warnings of internal rifts.
As the US military went on the offensive in the Sunni heartland of Iraq, an Al-Qaeda-linked group, Ansar Al-Sunna, posted a video on the Internet showing the beheading of a Shiite Iraqi man it accused of spying for US forces.
But 10 former Turkish hostages arrived in Baghdad after being released by their kidnappers, despite their employer defying their demands and vowing his construction firm would stay in Iraq.
On the international front, the UN`s nuclear watchdog raised concerns about missing equipment from Saddam Hussein`s regime that could be used to build a nuclear weapon.
In a letter to the Security Council, the International Atomic Energy Agency said it was concerned about the "widespread and apparently systematic" dismantling of entire buildings that contained specialised equipment.
US warplanes struck Fallujah, the epicenter of the Sunni Muslim rebellion, three times Tuesday and raided at least seven mosques in Ramadi, arresting a senior cleric.
US marines dropped a 500-pound (250-kilo) bomb on insurgents on the eastern fringes of the city late Tuesday after a firefight, a military spokesman said.
A first raid targeted Al-Haj Hussein restaurant in central Fallujah, famous across central Iraq for its kebabs. Four people were killed and six wounded, including restaurant staff, hospital sources said.
The US military said it was a known meeting place for Iraq`s most wanted militant Abu Mussab al-Zarqawi`s radical Unity and Holy War group.
Four hours later, US aircraft returned to strike the battle-scarred city, considered a hub for insurgents, destroying a suspected Zarqawi hideaway, the military said.
The military has intensified its blistering air strikes on Fallujah since September, saying it is seeking to restore law and order in Iraq by elections planned for January.
Also in the restive Al-Anbar province of western Iraq, US marines and Iraqi forces carried out pre-dawn raids on at least seven mosques in Ramadi, sparking shoot-outs in which two Iraqis were killed, the military and hospital sources said.
The Committee of Muslim Scholars, an influential Sunni body which represents 3,000 mosques, said the Americans and Iraqis had arrested their representative for Al-Anbar province, Sheikh Abdul al-Aleem al-Sadi, and his son.
The organisation said troops had raided 30 mosques across Ramadi, but the US marines had no immediate confirmation.
As the Sunni Muslim insurgency raged on, Shiite rebel Moqtada Sadr`s rebellion against the Americans appeared to be winding down as the preacher called on his followers to disarm under an agreement with the Iraqi government.
In Baghdad, dozens of Sadr`s Mehdi Army militiamen and arms dealers lined up outside a police station to sell weapons to police on the second day of a five-day period for the fundamentalist movement to disarm in Sadr City.
After the disarmament drive`s slow start on Monday, Iraqi officers were more hopeful that six months of clashes in the overcrowded slum between the Mehdi Army and US troops might finally be coming to an end.
"Hundreds of medium to heavy-sized weapons have been handed in. So far I would say it safely exceeds 1,000," Sadr City national guard commander Colonel Mehdi Zayer told AFP.
Under the terms of the deal, described as a loose verbal pact, there is a test period for the weapons surrender after which the Iraqi army is to move in and patrol Sadr City, where the Shiite militia has ruled by the gun.
But the US commander for Sadr City, Colonel Abe Abrams, warned that conflict was looming with at least two of Sadr`s aides refusing to disarm.
Abrams singled out Sadr lieutenants Abdul Hadi al-Darraji and Qais Khaazali for refusing to obey the disarmament order, saying they presented "a clear and present danger to the security situation in Iraq and right here in Baghdad."
A Sadr negotiator denied the two were resisting their leader, claiming everyone in the movement was on board.
Elsewhere, Iraqi police arrested a suspected member of Osama bin Laden`s Al-Qaeda group in Najaf, according to the police chief in the Shiite holy city.
Zarqawi`s armed group claimed a car bombing in the northern city of Mosul on Monday that killed two Iraqis and an American soldier and wounded 27 others.
Another militant group posted a video on the Internet of the beheading of a purported Turkish contractor and a Kurdish translator accused of working with US troops.
A member of Mosul`s governing council, Abdelmajid Ibrahim al-Antar, was shot dead in the latest in a string of assassinations of public servants.
Former Iraqi president Saddam Hussein, in US custody since his capture 10 months ago, underwent a hernia operation two weeks ago at a Baghdad hospital, Iraqi and US officials said.
In Ankara, Iraqi Kurdish leader Massoud Barzani said the oil-rich city of Kirkuk in northern Iraq had a Kurdish "identity" and vowed to fight any force trying to oppress its people.
US Defense Secretary Donald Rumsfeld appealed in Romania to his fellow NATO defense ministers to do anything they could do to help Iraqi security forces.
US officials are concerned that NATO trainers will not be on the ground in Iraq until next year, too late to have an impact before crucial January elections.