The explosion, in the mostly-Shiite Jadida district, was thought to have injured at least 11 others, the BBC reported Monday.

Earlier Monday, British and Iraqi troops raided a Basra police station, rescuing 76 prisoners believed to be in danger of execution by local authorities.

The raid followed the arrests Saturday of high-ranking leaders of the Basra Serious Crimes Unit.

The raid involved 1,000 troops and did not result in any casualties, CNN reported.

"The serious crimes unit themselves were guilty of serious crimes," British Maj. Charlie Burbridge said.

Burbridge said the unit "would take people in the middle of the night and they would never appear again."

He said the raid, which was authorized by Iraqi Prime Minister Nuri al-Maliki, was based on intelligence that the unit was "likely to start executing the prisoners, so we had to move fast."

Meanwhile, an Iraqi interior ministry official said a Baghdad suicide bomber detonated himself inside a bus Monday morning, killing at least two people and injuring seven.