British jets fire on Basra militia

The show of force came after US pilots strafed suspected insurgent positions in the first air attacks since the launch of the Iraqi-led clampdown on Shia insurgents which has sparked violence across Iraq.

But the US strike prompted confusion when British officials initially said that coalition planes had dropped bombs in the city.

Major Tom Holloway, British military spokesman in Basra, later clarified that "incidences of weapons release" from the US aircraft in fact referred to strafing suspected insurgent positions.

Pilots swept low to unleash a hail of cannon rounds on a militia mortar firing point and a building believed to be being turned into an insurgent stronghold, he said.

During the course of the fighting, RAF aircraft - believed to be Tornado jets - followed suit, strafing patches of waste ground in a dramatic warning shot to suppress militia activity, the Ministry of Defence said.

It is understood that RAF aircraft carried out four separate shows of force on a day of sporadic fighting in the city which was handed over to full Iraqi control by British forces just three months ago.

With fighting spreading across Shia areas of Iraq, US President George Bush described the operation as a "defining moment in the history of a free Iraq".

The operation, involving thousands of Iraqi troops and police, is the first military action of its type in Basra since the handover.

But the action, overseen by prime minister Nouri Maliki, threatens to split the Shia community at a time when the Sunni insurgency has shown signs of receding following the US troop surge.