BAGHDAD (Reuters) - More than 1,000 U.S. and Iraqi forces have begun operations against al Qaeda in Iraq's northern city of Mosul, the U.S. military said on Monday, paving the way for what Iraqi officials say will be a decisive strike.
Last month, Iraqi Prime Minister Nuri al-Maliki announced plans to drive Sunni Islamist militants out of Mosul, Iraq's third-largest city, which U.S. commanders call al Qaeda's last major urban stronghold.
While the United States says attacks have fallen across Iraq by 60 percent, U.S. commanders have said al Qaeda remains a great threat to security and a dangerous enemy.
Tens of thousands of U.S. and Iraqi soldiers are taking part in several offensives in Iraq's northern provinces, where al Qaeda and other insurgents regrouped after being ousted from western Anbar province and around Baghdad last year.
Extra Iraqi troops, backed by helicopters and tanks, have been sent to Mosul. The U.S. military said Monday an operation had begun to clear insurgents out of bases in the east of the city, where five U.S. soldiers were killed last month.
"As of right now there are 1,000 plus ISF (Iraqi Security Forces) and CF (Coalition Forces) conducting (the) ... operation," said Maj. Gary Dangerfield, a spokesman for U.S. forces in the area.
"It is a preparation for the military operation which will be conducted soon to take control of volatile areas," said Wathiq al-Hamadani, police chief for Nineveh province, where Mosul is located.
While Iraqi officials have spoken of "cleansing" Mosul of al Qaeda fighters, U.S. commanders have been less emphatic, saying the forthcoming offensive was part of wider operations.
U.S. Maj. Gen. Mark Hertling, commander of troops in northern Iraq, said al Qaeda fighters were being pushed out of northern cities and into more remote areas. He also said some fighters were leaving Iraq, with plans to return.
"We are seeing some indications in various forms that there is an attempt at reconsolidating outside of the country and coming back in, so we're watching the borders very closely," Hertling told reporters at the Pentagon.
"Some of them we have seen specifically leaving to Syria, some of them are going back to Saudi Arabia and Qatar," he told reporters by videolink from Iraq.
Dangerfield said Al Qaeda currently launches about 20-25 attacks a day on coalition forces, although most fail.
However in a reminder of the group's influence, a suicide bomber used a fuel tanker to kill four Iraqi soldiers and wounded seven others in a blast in western Mosul on Sunday.
Last month a huge blast in a building the U.S. military said al Qaeda used to store explosives killed up to 50 people.
(Additional reporting by Kristin Roberts in Washington)
Editing by Patricia Zengerle