A suicide attacker killed four Iraqi security personnel and injured six others on a bridge in the city of Heet, west of Baghdad, on Friday, a security source said.The attacker was driving his booby-trapped car at Al-Baker Bridge and detonated the explosives when he reached a checkpoint over the bridge killing three soldiers and a policeman, as well as injuring six servicemen, the source told KUNA.Heet is 190 kms west of Baghdad.The attack took place shortly after the Defense Ministry announced the killing of more than 40 Al-Qaeda gunmen.Ministry spokesman Major-General Mohammad Al-Askari, speaking to KUNA, said military forces killed 40 terrorists and destroyed four hideouts in Fallujah.