SANGIN VALLEY (Afghanistan), April 30: British troops swept into a Taliban stronghold lush with opium poppy fields on Monday, launching a new Nato operation in southern Afghanistan just as US-led forces reported killing 136 militants in the west.

British soldiers quickly came under fire as they patrolled among the high-walled compounds and deep irrigation ditches of militant-held Sangin Valley in Helmand province. Troops responded with gunfire and artillery.

There were no immediate reports of casualties in Operation Silicon, the latest stage in Nato's biggest-ever offensive against the resurgent Taliban militia in the volatile south.

However, in the western province of Herat, the US-led coalition reported the bloodiest fighting in Afghanistan since January, during three days of clashes in the Zerkoh Valley.

Acting on intelligence indicating Taliban activities, coalition and Afghan forces attacked the insurgents and called in an airstrike, destroying seven Taliban positions and killing 87 fighters during a 14-hour engagement on Sunday, a coalition statement said.

Another 49 Taliban were killed two days earlier by a combination of gunfire and an airstrike, it said. One US soldier was also killed.

The casualty figures could not be independently confirmed, although police said that “a large number of people” had died in the fighting.—AP