Four British soldiers have been killed by a roadside explosion near Basra, southern Iraq, the Ministry of Defence has confirmed.
A civilian translator is also reported to have been killed in the bomb blast, which targeted a Warrior patrol.
A fifth soldier was also "very seriously injured" and is being treated in the military hospital in Basra.
This latest incident brings the total number of UK troops killed in operations in Iraq to 140.
An MoD spokeswoman said: "It is with deep regret that we can confirm that four British soldiers and a civilian interpreter were killed in a roadside bomb attack against a Warrior patrol west of Basra.
"Next of kin are being informed and no further details will be released until this process is complete."
Further deaths
Two other British soldiers were also killed in Iraq this week, also while on patrol in the Basra area.
Of those soldiers who have died in Iraq, 108 are classed as having been killed after hostile action, while 32 have died from illness, non-combat injuries or accidents, or the cause of their death is still unknown.
Meanwhile, eyewitness reports say a US helicopter has come down in southern Iraq after apparently coming under heavy fire from insurgents.
The reports say the helicopter came under attack near Latifiya, 40km (25 miles) south of the capital, Baghdad.
No information is currently available on any casualties and the US military says it is investigating.