Iraqi and US troops move against al Qaeda in north

(Adds U.S. military confirmation, paragraphs 5 and 6)

BAGHDAD, May 10 (Reuters) - Iraqi and U.S. troops launched an operation in northern Iraq on Saturday to try to drive out al Qaeda militants regrouped there, the Iraqi military said.

Lieutenant-General Riyadh Jalal Tawfiq, the commander of Iraqi armed forces in Nineveh province, said the operation would particularly target al Qaeda fighters in the city of Mosul, regarded as the group's last urban stronghold in Iraq.

Tawfiq said a vehicle curfew had been imposed throughout the province, whose capital is Mosul.

"I declare the beginning of the military operation today to clean the province of al Qaeda remnants," Tawfiq told reporters. "I call on all the clerics and the heads of tribes to support the security forces in our effort to kick al Qaeda out."

A U.S. military spokeswoman for Iraq's northern region, Major Peggy Kageleiry, confirmed an operation was under way.

"The GOI (government of Iraq) ... is undertaking a new phase of operations in Mosul to counter the terrorist threat," Kageleiry said. "This ... Iraqi-led series of operations continues to be closely supported by (U.S.) ... forces."

Tawfiq said large numbers of Iraqi forces had been sent to Nineveh, although he declined to give details. Residents said they saw U.S. fighter planes flying over Mosul.

In January, Prime Minister Nuri al-Maliki announced plans to drive al Qaeda out of Mosul, Iraq's third-largest city. U.S. military officials said at the time it would take months to clear the ethnically and religiously mixed city.

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.

A build-up of U.S. troops last year and support from Sunni Arab tribes that turned against al Qaeda allowed the military to conduct a series of offensives that largely pushed the militants out of Baghdad and the western province of Anbar.

Many regrouped in northern provinces, such as Nineveh.

However, U.S. commanders say al Qaeda in Iraq, although weakened, can still carry out large-scale attacks.

Al Qaeda in Iraq shares the name and ideology of Osama bin Laden's network, which was blamed for the Sept. 11, 2001 attacks in the United States.

Structural and operational ties between the two are unclear but the U.S. military says al Qaeda in Iraq is largely foreign-led. Its foot soldiers are mainly Iraqis. (Additional reporting by Tim Cocks; Writing by Tim Cocks; editing by Andrew Dobbie)