A speeding suicide truck bomber slammed into a police station in the northern Iraqi city of Mosul on Friday, killing one policeman and wounding 20 other people, authorities said. The bomber made a sharp turn as he approached the police station in the southwestern parts of the city, then rammed his truck through an iron barrier, hitting a sandbagged wall beyond it and detonating his vehicle near the station's main building. The blast shook the entire complex, witnesses and police said. Mosul is Iraq's third-largest city and al-Qaida's last urban stronghold in the country. Suicide bombings - a hallmark of al-Qaida's attack style - have continue to threaten the city, which US troops must leave by June 30, under an agreement with the Iraqis. The approaching deadline has raised fears about what is to come after American soldiers depart. The wounded in Friday's blast were mostly policemen, and all were taken to a nearby hospital, a police officer with the provincial command said. He spoke on condition of anonymity because he was not authorized to talk to the media. Mosul has been relatively quiet in recent weeks compared to Baghdad where attacks killed at least 53 people this week. Meanwhile, Iraqi police in the southern city of Basra said Friday they arrested 65 people in overnight raids after an attack on a US convoy in the area and the kidnapping of two guards working for a local Iraqi security firm the previous day. The arrested included 20 people who were already on a wanted list and 45 others, mostly militiamen, said the city's police spokesman Col. Karim al-Zeidi. The US military said an American convoy was hit by a roadside bomb near Basra on Thursday, but there were no casualties. Separately, al-Zeidi said two guards working for an Iraqi security firm were abducted late Thursday from their car, which was left by on the side of the road near Basra along with the guards' weapons. Their identities and the company they worked for were not immediately known.