A roadside bomb has killed two British soldiers in southern Iraq.
Concerns have grown about security in Basra
The Ministry of Defence said two members of the Queen's Dragoon Guards were killed in Basra at 1830 BST on Sunday, and two others were injured.
The attack came on the day British forces seized what they described as their largest cache of weapons yet.
It brings the UK death toll in Iraq in May to nine, after five were killed when a Lynx helicopter crashed and two others died in a roadside bomb.
At the weekend, President Jalal Talabani urged Iraq's new government to help improve security in the Basra area.
Later on Monday, it was announced that two British television journalists had been killed by a roadside bomb in the capital, Baghdad.
Paul Douglas, 48, and James Brolan, 42, who both lived in London, had been working for American network CBS news, the company said.
Following Sunday's fatal attack on the UK troops, an MoD spokesman said: "The soldiers were from the Queen's Dragoon Guards, part of the Basra City Battlegroup. The next of kin of those killed have been informed."
The names of the dead are expected to be released on Tuesday.
The incident happened in Gizayza, north-west Basra, during a routine patrol in an armoured Land Rover, in support of operations to disrupt the insurgency.
Defence Secretary Des Browne said: "It was with profound sorrow that I heard of the tragic deaths last night of two British soldiers.
"Our thoughts are with the family and friends of these brave men. I am told that two other soldiers have sustained minor injuries."
Military spokesman Major Sebastian Muntz said Sunday's attack followed "some very successful operations over the last few days".
"The broad mass of the population support what we are doing and are very much on side," he said.
"Clearly there are elements of the population that are trying to disrupt our activity and don't want the secure environment that our soldiers are trying to provide."
Liberal Democrat defence spokesman Nick Harvey said such incidents were "all too frequent".
"It is becoming increasingly dangerous for our troops. We need a strategy, making it clear to all, precisely what we're trying to achieve in Iraq."
The Queen's Dragoon Guards, which can trace its history back to 1685, recruits largely from Wales and its regimental museum is in Cardiff. They have been based in Osnabruck, Germany, since 2003.
Basra is Iraq's second-largest city and the focus of the British military operation in southern Iraq, which has about 7,000 troops in the region.
The BBC's Andrew North in Baghdad said the dangers were increasing for British troops in the south, and such incidents put a handover date further back.
Adam Morris, 19, and Joseva Lewaicei, 25, died in a roadside bomb attack near Basra a fortnight ago.
There were also clashes between local people and British forces earlier this month after a Lynx helicopter carrying five service personnel crashed after an apparent rocket attack.
In Sunday's discovery of weapons, troops from the Queen's Royal Hussars believe they found enough what was material to make dozens of explosives. One device was disguised as roadside debris.
Other equipment seized included rocket-propelled grenades, a sniper rifle, a sub-machine gun and military disguises.