A suicide bomber has killed 28 people at a police recruitment centre in the Iraqi capital Baghdad.At least 57 other people were injured in the attack, which was reported to have been carried out by a bomber who drove his motorcycle into a crowd. The victims were queuing outside the academy when the bomber struck. Police recruitment centres have been a popular target for insurgents. Some of the dead were policemen, while others were police recruits and civilians. This is the deadliest suicide strike reported in Iraq for nearly a month. The academy has been targeted before. In 2005 two female suicide bombers attacked the same building, killing 40. The level of violence in Iraq has dipped significantly since 2007, but it remains a feature of daily life for many Iraqis.