Two soldiers, an American and a Canadian, were killed in a major Taliban attack on a base in the Afghan province where thousands of British troops are to deploy in the coming months.
The Taliban said the attack in Helmand was the start of a spring offensive against Afghan government and Western forces.
The attack, in which 32 Taliban fighters were killed, was a reminder of the scale of the insurgency British troops will face in Helmand. US-led forces at the base had to call for air support to repel the offensive. Five other soldiers, including three Canadians and one American, were wounded.
"The weather is warming and Taliban attacks on coalition and Afghan forces have begun," a Taliban spokesman, Mullah Mohammed Hanif, said by telephone from a secret location.
Over the next few months, 3,300 British troops will deploy in Helmand. Taliban commanders say they have 600 suicide bombers waiting for them.
The base which was attacked yesterday, in Sangin district, is used by US-led forces, and it did not appear that any British troops were there at the time.
This was the latest in a series of full-scale assaults on American bases by the Taliban. They attack in large enough numbers to cause US-led forces difficulty in repelling them and, though the Americans regularly beat them back, it is not without heavy fighting.
In yesterday's skirmish, US forces said they killed 12 Taliban insurgents in repulsing the initial assault, and 20 more after they pursued the attackers to their own base. They found large stores of weapons, bomb-making supplies and ammunition, and US planes bombed two buildings.
"The capturing of these two compounds produced significant intelligence and allows us to continue to put pressure on the enemy," said Brigadier-General Anthony Tata of the US military.
In a separate attack, two Afghan police were killed when insurgents tried to take control of a police post inside the city of Kandahar.
The Taliban insurgency has been steadily intensifying across southern and eastern Afghanistan, and there are clear signs they are growing in confidence. Sixty US troops were killed last year in the country.Reuse content