By Hilary Andersson BBC correspondent near Khost

Around 200 British marines in Afghanistan have been fanning across villages in the south-eastern area near Khost as part of Operation Buzzard, the operation where British soldiers are working in populated areas.

Company Xray, as it is called, is camped out of a flat, dusty plain just a few kilometres from the Pakistani border near the Afghan town of Khost.

The new mission, operation Buzzard, involves more than 300 troops and aims to secure turbulent south-eastern Afghanistan - the area south of the mountainous Khost region, down to the border with Pakistan.

The month long mission comes about two weeks before next month's grand tribal council, which will choose a new transitional government in the country.

Civilian patrols

The marines have dug themselves into shallow holes in the ground where they eat and sleep.

The plain is entirely exposed and the marines are cautious but say they do not feel threatened, even though this is the first time they have operated in civilian areas.

All day they have been patrolling through the villages here, heavily armed but on foot, and meeting tribal elders.

The marines deployed at night over three days

They are trying to present a friendly face with a view to extracting information about the whereabouts of al-Qaeda fighters.

The British troops have had a very warm reception here.

Many locals hope they are here to bring food and water to the area.

Some have no clear idea what the military purpose of their visit is, since al-Qaeda fighters left the area at least a month ago and are reported to have fled over the border to Pakistan.

British troops have been criticized for allowing the enemy to slip away.

But the Royal Marines say their fight now is less to do with gun battles than it is trying to win over the local support for Afghanistan's moderate leaders.

This is so that in the future, al-Qaeda fighters will not be allowed to return to the area.