UK troops start Afghan action

The troops are hunting al-Qaeda and Taleban fighters

Hundreds of British marines have gone into action in the mountains of eastern Afghanistan - their first full combat operation since the Falklands conflict.

Royal Marines from 45 Commando, part of 3 Commando Brigade, are working with US and Afghan troops to track down any remaining Taleban and al-Qaeda fighters in a high mountain valley.

The terrain is very steep and mountainous, some of them are above the snowline

Colonel Paul Harradine

It is thought they have been targeting an area just south of the Tora Bora mountains, where the US carried out an intense bombing campaign in December.

Lieutenant Colonel Paul Harradine, in Afghanistan, said the marines' task was to "destroy any enemy they come across in that area, and then to make that area unusable as a base".

Defence analysts said the troops could expect all kinds of fighting, including guerrilla-style, hand-to-hand combat, in extremely inhospitable terrain.

Colonel Harradine would not confirm whether there had yet been any direct combat, but said there had been no casualties so far.

Shadow defence spokesman Gerald Howarth said he understood the valley had already been swept, and the troops were simply "re-covering" it to check al-Qaeda had not regrouped.

'Very cold'

Colonel Harradine would not give any details about the strength of opposition the troops were facing, but said: "Everything is going well."

He said the difficulty of the operation "shouldn't be underestimated" - not least because of the harsh Afghan environment.

It's a very difficult operation... but they're up for it

Colonel Harradine

"It's a very difficult operation, they're working at an altitude of about 9,500 ft (3,000m).

"The ground they're working on is very rugged, the terrain is very steep and mountainous, some of them are above the snowline, it's very cold at night, (there are) strong winds and rain.

"But they're up for it. They're Britain's mountain and cold weather experts - I'm confident they'll do a great job."

He would not give any estimate of how long the operation would last, merely saying it would continue "until it is complete".

'Dangerous, difficult work'

BBC defence correspondent Richard Lister said this operation was better resourced, planned and equipped than last month's US-led Operation Anaconda, just north of the Tora Bora, in which eight American men were lost.

But defence specialist Professor Michael Clark said it remained an extremely dangerous operation.

"It would be surprising if there aren't some casualties, because this is the worst work that troops can be asked to do, to clear out defences one by one... that's always dangerous, difficult work."

Up to 900 Royal Marines are currently in Afghanistan, and by the end of April, about 1,700 are expected to be in the country.

Intelligence sources told BBC News one aim of Ptarmigan was to establish the scale of the threat posed in Afghanistan by al-Qaeda and Taleban fighters.

They thought only hundreds, rather than thousands, remained in the country - but many more could be waiting across the border in Pakistan.

Osama 'objective'

The marines, who have been training in the mountain regions for several weeks, are expected to remain for at least another three months.

Brigadier Roger Lane said they were in for the "long haul", and the MoD said a secondary aim of the operation - code-named Ptarmigan - was to prepare the troops for similar joint operations in Afghanistan in the future.

Colonel Harradine said the troops had been eager to start work, and morale was "very high".

"This is precisely why these young men join the Royal Marines - to join operations".

If we get knowledge of where [Osama Bin Laden] is... we will take the appropriate action to bring him to justice

Armed forces minister Adam Ingram

Armed forces minister Adam Ingram told BBC Radio 4's Today programme the operation could include capturing Osama Bin Laden.

"If we get knowledge of where he is... we will take the appropriate action to bring him to justice - that remains one of the prime objectives," he said.

He would not confirm whether Pakistan would allow allied troops to cross the border in pursuit of the enemy, but did say the allies had "good relations" with its government.