Violence continued to flare across Iraq on Thursday. A suicide bomber killed at least eight people and wounded dozens of others when Sunnis and Shiites gathered for a goodwill visit at a mosque in the country’s restive northern Diyala province, police said.

Also Thursday, a car bomb killed at least four police officers, including a colonel, in the ethnically charged city of Kirkuk, where U.S. soldiers remain actively engaged in a peacekeeping mission to ease tension along a disputed border between Iraq’s Kurdish and Arab populations.

Combined, the attacks stoked fears of growing ethnic violence in northern Iraq as U.S. military leaders have been asking the Iraqi government to decide soon whether it wants U.S. forces to stay beyond 2011.

Also Thursday, Iraqi police Brig. Gen. Mohammed Aala Jassim, a high-ranking member of Iraq’s fledgling air force, was killed by gunmen who used silenced weapons to attack his car as he drove home from work in Baghdad.

The U.S. military also announced that a soldier had died Wednesday in a noncombat-related incident in southern Iraq. No other details about the death were released, pending notification of the soldier’s family.