BAGHDAD—Iraqi insurgents painted red the treacherous road to sovereignty yesterday, launching a five-city killing spree that left about 100 people dead and 320 wounded.

The northern city of Mosul was hardest hit when multiple morning car bombings killed 62 people, including one U.S. soldier, and wounded 220.

Dozens more died in almost simultaneous attacks on Iraqi security forces compounds in the Sunni Muslim strongholds of Falluja, Ramadi and Baquba.

Most of the victims in Mosul — often touted as a success story in restoring order in Iraq — were killed when at least four car bombs rocked the police academy, two police stations and the al-Jumhuri hospital.

U.S. troops recaptured the Sheik Fathi police station in a hail of gunfire, and Iraqi troops raided a nearby mosque used by insurgents, the U.S. military said. Mosul's governor imposed an overnight curfew.

Two U.S. soldiers were killed and seven were wounded during an ambush in Baquba, northeast of Baghdad, where running battles continued into the afternoon.

Four people were killed in a separate suicide attack in southern Baghdad when a man carrying a black Samonsite briefcase blew himself up at a checkpoint.

Later, the key arteries leading to the Iraqi capital were sealed with joint U.S.-Iraqi military checkpoints in an attempt to intercept additional bombers trying to enter the city.

The co-ordinated, cross-country assaults were among the deadliest demonstrations of terror timed to disrupt next week's formal handover to Iraqi rule.