A Danish soldier and two British soldiers from a Nato-led force were killed in the southern Afghan province of Helmand, where troops are fighting a Taliban insurgency, their governments said on Monday.
The Taliban has vowed to intensify attacks using suicide bombings in their campaign to expel foreign troops and overthrow the government of President Hamid Karzai.
The British soldiers were caught in a blast while on a routine patrol on Sunday.
"The soldiers were conducting a patrol in the vicinity of Kajaki, Helmand Province, when the vehicle they were travelling in was caught in an explosion," the British defence ministry said in a statement.
A statement from the Nato-led force said the soldiers were taken to a British base in Helmand province after the attack.
"The soldiers were airlifted to the medical facility ... and one soldier was pronounced dead on arrival and the other died subsequently," it said.
Britain, a major troop contributor to the Nato force fighting Taliban and Al Qaeda insurgents, has about 7,800 troops in Afghanistan, mostly in Helmand, a largely desert province cut in two by a river valley flanked by lush, fertile land that produces nearly half the world's opium.
The deaths brought to 91 the number of British troops killed in Afghanistan since the Taliban were ousted from power in late 2001 by US-led forces.
More than 30 foreign troops have been killed in Afghanistan so far this year, and more than 200 were killed last year.
The Danish soldier was killed on Monday, and two comrades were wounded, as they fought alongside British troops in an offensive supported by tanks, artillery and helicopters in Helmand, according to Danish Army Central Command.
Denmark has about 550 combat troops in Afghanistan. Three soldiers were killed this month and 10 have died in combat so far. Three others were killed trying to dismantle a mine in 2002.
In a separate attack on Monday, a roadside bomb killed three private security guards working for a road construction company in Kandahar province, which is also in the south, said provincial government official Niaz Mohammad Sarhadi.
The militants regularly attack infrastructure projects, which the government and its Western backers hope can win over the population and undermine any support for the Taliban. (Reuters)
Two British soldiers and one Dane killed in Afghanistan