Troops from a US Marine company in Afghanistan have been under almost constant fire since entering the country with 4,000 other troops during the week.

Since flying in by helicopter to Mian Poshteh in Helmand province, troops from the 2/8 infantry battalion have been held down by insurgents.

The 200 Marines are still fighting to hold position and have had to call in helicopter gunships for assistance.

Taliban fighters have been using small arms, rocket-propelled grenades and rockets against the Marines

One Marine was killed in the hostile fire in the first day of the battle, while others are succumbing to the intense heat in the area and are being evacuated to medical facilities.

The Marines are in an area which is criss-crossed by canals and irrigation ditches which were built by the US in the 1950s and 1960s to aid agriculturalists in the region.

Opium has become the mainstay on local farms, where the owners have been forced by the Taliban insurgency to grow the crop.