There was further evidence of a major coalition offensive when Iraqi police reported that Polish troops had killed the head of al-Sadr's office in Kerbala, militant cleric Murtada al-Mussawi, during clashes in the holy Shi'ite city today. But there was an immediate defiant response from another al-Sadr commander in Najaf, who claimed an unspecified number of coalition soldiers had been captured in street clashes.