* Maliki offers gunmen cash and freedom from prosecution
* Fighters have to hand in heavy and medium weapons
* Suicide bomber kills four in Falluja
(Adds Sunni Arab leader comments, bomb attack)
By Khalid al-Ansary
BAGHDAD, May 16 (Reuters) - Iraqi Prime Minister Nuri al-Maliki, leading an offensive against al Qaeda in the north, offered cash and freedom from prosecution on Friday to fighters who give up their weapons within 10 days.
Maliki made the amnesty offer in the northern city of Mosul, where he has been supervising a U.S.-backed campaign aimed at delivering a fatal blow to Sunni Islamist al Qaeda in the city and surrounding Nineveh province.
Many al Qaeda gunmen have regrouped in Nineveh after being pushed out of Baghdad and other areas. The U.S. military says Mosul is al Qaeda's last major urban stronghold in Iraq.
"We have decided to grant amnesty to those who joined the armed groups on condition they hand over heavy and medium weapons to the security forces," Maliki said in a statement.
He did not elaborate, but this would mean weapons such as rocket-propelled grenade launchers and mortars. Iraqi law allows each household to have an AK-47 assault rifle.
Those who turned in arms would be paid a cash reward, Maliki said, without saying how much.
But in a condition that could limit the amnesty's reach, he said it only applied to "those who did not commit crimes against civilians or stain their hands with blood".
U.S. officials blame al Qaeda in Iraq for most big bombings in the country, including an attack on a Shi'ite shrine in Samarra in February 2006 that set off a wave of sectarian killings that nearly tipped Iraq into all-out civil war.
"This operation ... will achieve its goals: imposing law, preserving order, saving (Mosul) from the evil of terrorist groups and the remnants of the past regime," Maliki said.
An Iraqi security source said police and soldiers had raided some towns on the Syrian border as part of the operation and detained a few suspects who were turned over to U.S. forces.
Foreign al Qaeda fighters often enter Iraq through Syria, especially where the border meets Nineveh.
MALIKI REMAINS IN MOSUL
An influx of additional U.S. troops last year and a decision by Sunni Arab tribes to turn against al Qaeda has enabled U.S. and Iraqi forces to push the militants out of Baghdad and the western province of Anbar, their former stronghold.
Tribal leaders welcomed the offensive in Mosul, a Sunni Arab dominated city.
"Al Qaeda has ruined this city. We have sacrificed our sons in the police in the fight against them," Sheikh Abdul-Razzaq Mijbil, head of the Sunni Arab Jubouri tribe said.
"We have to kick them out."
But U.S. military commanders warn that the group still has the capability to carry out large-scale attacks.
A suicide car bomber struck a police station in the former al Qaeda stronghold of Falluja, western Iraq, on Friday, killing four policemen and wounding nine other people, police said. The attack bore the hallmarks of the militant group.
Police beat up a Reuters cameraman and a photographer when they tried to film the aftermath of the bombing. The photographer was admitted to a hospital.
Officials have not said how long Maliki will remain in Mosul. He flew to Iraq's third largest city on Wednesday.
In late March, Maliki also took charge of a military operation against Shi'ite militias in the southern oil city of Basra. That offensive hit trouble when the Mehdi Army of Shi'ite cleric Moqtada al-Sadr put up fierce resistance, and clashes spread to other towns in southern Shi'ite Iraq and also Baghdad.
While fighting soon eased in southern Iraq, heavy clashes with security forces continued in Baghdad until a deal between Sadr's opposition parliamentary bloc and the ruling Shi'ite alliance helped begin to restore calm earlier this week.
On Friday there were few reports of clashes in the cleric's Baghdad stronghold of Sadr City, residents said. (Writing by Tim Cocks, editing by Dean Yates and Richard Williams)