The Ministry of Defense said three other soldiers were hurt, one seriously, in the blast, which took place on Tuesday morning in the southern port of Umm Qasr in Basra province.

It gave no further details of the incident, nor of the identities of the soldiers, who were from the 7th Armoured Brigade, the main British force in Iraq.

"I can confirm that a British soldier died from injuries sustained as a result of an explosion at approximately 8:34 local time in Basra province," a ministry spokesman said.

The three injured soldiers were being treated at Britain's Shaiba base nearby.

The spokesman confirmed that the death was the 100th in the Iraq operation.

"Every death in Iraq is as tragic, whether it's the 100th or the 99th or the first. They are all equally tragic," he said. Of those who died during the operation, 77 are listed as having been killed in action and the rest through accident or illness.