Taliban say Afghan offensive is on, 20 dead

KABUL, Mar 29 (Reuters) Insurgents in Afghanistan attacked a US base today, in which two foreign troops and at least 12 militants were killed, the US military said.

Violence has intensified in recent months and the Taliban have been vowing to unleash a wave of attacks as part of their campaign to oust foreign forces and the Western-backed government.

The Taliban said their fighters attacked the US base in the southern province of Helmand.

In other violence, a roadside bomb killed six Afghan soldiers yesterday in Helmand's Sangin district, an Afghan commander said.

One of the foreign troops killed in the attack on the base was American. The US military did not identify the nationality of the second who died in the attack by a ''significant'' insurgent force on a forward operating base.

''Coalition forces employed a variety of combined arms to include close air support and are believed to have killed at least a dozen enemy insurgents,'' the US military said in a statement.

Three members of the US-led force and one Afghan soldier were wounded, it said.

Twelve US troops have been killed in fighting this year. Nearly 60 Americans were killed in Afghan fighting last year, the worst for US forces since they invaded in 2001 to oust the Taliban.

The Taliban vowed more violence, saying their spring offensive had begun.

''The weather is getting warmer and Taliban attacks on coalition and Afghan forces have begun,'' Taliban spokesman Mullah Mohammad Hanif said by telephone from an undisclosed location.

Fighting traditionally picks up in the Afghan spring when snow blocking mountain passes melts.

Despite the rising level of violence, the United States is hoping to trim its force of more than 18,000 troops in Afghanistan by several thousand, while NATO partners, including Britain, Canada and the Netherlands are sending about 6,000 more.

British troops are based in Helmand but a spokesman for the force said he had no information about Wednesday's fighting.

Canadian troops are also based in the volatile Afghan south. A Canadian spokesman was not available for comment.

REUTERS SB RAI1237