Iraqi security forces arrested 14 suspected Al Qaeda members in western and northern Iraq, including three who were formerly detained by U.S. troops in the country, local police officials said Thursday.

Six men arrested in Fallujah were wanted for allegedly planning attacks in and around the city, which is located 40 miles west of Baghdad, said the city's police chief, Col. Mahmoud al-Isawi.

"The group is believed to be behind many murders and attacks against the citizens and the police forces," al-Isawi told The Associated Press, without specifying when the arrests or the attacks took place.

Fallujah is a city in western Anbar province that was a hotbed of Iraq's Sunni-dominated insurgency and the scene of some of the most intense U.S. fighting with militants, before becoming a model of security gains in the country.

Police detained the other eight suspects, one of whom was a woman, during a raid Tuesday on a suspected militant hideout in the oil-rich city of Kirkuk, 180 miles north of Baghdad, the police chief in the city, Jamal Taher, told the AP. Police confiscated roadside bombs and car bombs during the raid, he said.

Two of the men in Fallujah and one in Kirkuk were previously detained by U.S. forces but were subsequently released, said the two police chiefs.

As part of an agreement between the two countries that took effect Jan. 1, Iraqi authorities have begun reviewing the cases of U.S. detainees to decide whether to free them or press charges. Thousands have been freed because there is little or no evidence against them, but some are suspected of having returned to violence.

The two men in Fallujah were suspected by the U.S. of having links with insurgents but were released in July for lack of evidence, said al-Isawi. They had been held at Camp Bucca, a military base in southern Iraq that served as the largest U.S. detention site in Iraq before it was closed down last month, said al-Isawi.

The U.S. is scheduled to turn over its detention system to the Iraqi government by early 2010.

Iraq is struggling to handle tens of thousands of detainees held in overcrowded prisons and makeshift jails. Many were detained in past years on suspicion of links to the Sunni-led insurgency or Shiite-dominated militias during Iraq's sectarian violence in 2006 and 2007.