BAGHDAD, May 6 (Xinhuanet) -- A car bomb Friday targeted a police patrol in the northern city of Mosul, killing four police commandos and five others, police said.

    Iraqi security forces immediately cordoned off the scene and searched the area, as ambulances evacuated the victims to a nearby hospital.

    Earlier, seven policemen were killed and several others wounded when a suicide bomber drove an explosive-laden vehicle into a police bus near a checkpoint manned by Iraqi army and policemen on a bridge in Tikrit.

    The two attacks were the latest in a surge of attacks against Iraq's fledging security forces.

    At least 18 suicide bombings have occurred in Iraq, causing about 500 casualties, since the transitional government was approved by the parliament one week ago. Enditem