The suspected militants were killed or arrested in security operations from March 18 to 24 in Mosul, 390 km (240 miles) north of Baghdad and an Al-Qaeda stronghold, it said in a statement late on Thursday.

The suspects were accused of involvement in an extortion and assassination network that helped fund Al-Qaeda around Mosul. Its targets included oil companies and small businesses, the statement said.

Those killed were identified as the Al-Qaeda emir of northern Iraq, Khalid Muhammad Hasan Shallub Al-Juburi; economic security emir Abu Ahmad Al-Afri; and the suspected Al-Qaeda governor of Mosul, Bashar Khalaf Husyan Ali Al-Jaburi.

The military said three top suspected oil-extortion figures were among a dozen people arrested on March 24 in a security sweep.

"Without these individuals in the AQI (Al-Qaeda in Iraq) network, it is expected that AQI's ability to operate and restructure will be severely hindered," it said.

The joint US-Iraqi operations were carried out pursuant to a warrant from an Iraqi judge.