Suicide bomber wore vest as men line up at army training center . Bomber 's vest was loaded with 30 kilos of explosives , ball bearings . Deadly attack occurs on day with a number of violent incidents in Iraq . A recent campaign of bombings and shootings has targeted Iraqi forces , especially in the capital , where gunmen have attacked traffic police and attacked checkpoints , killing Iraqi troops . Iraq has been urged to increase security as U.S. troop drawdown nears .
Suicide bomber wore vest as men line up at army training center . Bomber 's vest was loaded with 30 kilos of explosives , ball bearings . Deadly attack occurs on day with a number of violent incidents in Iraq . Iraq has been urged to increase security as U.S. troop drawdown nears .