Kabul - Several militants were killed and 14 were arrested in western Afghanistan, while US marines and British forces launched a new major operation against a Taliban stronghold in a southern town, officials said on Tuesday.

Afghan and US-led coalition forces killed "several militants" and detained 14 others during a search operation in Khash Rod district of western Nimroz province on Monday, US military said in a statement.

The combined forces came under fire by rocket-propelled grenades and machine guns during the operation targeting a militant engaged in weapon movement to militants in the area, the statement said.

The joint forces responded to the militants' attack with small-arms fire and air strikes, killing several of the rebels.

Meanwhile, hundreds of US marines and British forces launched a major operation against a Taliban stronghold in Garmsir district in southern Helmand province on late Monday, officials said.

The US marines are part of the new 2,300-strong unit, who were deployed to southern provinces a few months ago to reinforce the NATO forces and to contain Taliban attacks during the spring and summer, the traditional fighting seasons in the region.

"The goal of this cooperative operation is to enhance the security for the Afghan citizens of one district in Helmand province," NATO-led International Security Assistance Force (ISAF) said in a statement.

The marines, who departed neighbouring Kandahar province on ground convoys and by airlift into the area through the past week, launched the operation from forward staging areas in Helmand province on late Monday, the statement said.

Helmand, which is the largest opium producing province in the country, is the Taliban's main stronghold in the country. There are nearly 8,000 British forces stationed in the province.

The deployment of new US marines allows the commander of ISAF to "rapidly" deploy the forces wherever it's needed to conduct "full-spectrum operations from humanitarian assistance missions to combat operations," the statement added.

Despite the presence of some 4,7000 ISAF troops from some 40 countries in the country and more than 140,000 Afghan security forces, the Taliban are still a force to be reckoned with. (dpa)