Up to 6,000 people have fled their homes in a southern Afghanistan district fearing NATO strikes amid a large-scale operation against Taliban militants, an official said Monday.

The mass exodus from Garmser, a remote district in troubled Helmand province, comes as NATO-led troops hunt Taliban militants and their allies in an operation that kicked off two weeks ago.

"Around 900 families, counting for about 5,000 to 6,000 people, have left the area," refugees ministry spokesman Shamsuddin Sarhadi told AFP.

The displaced families were being put up in a government-run camp in Lashkar Gah, the capital of Helmand which is 50 kilometres (30 miles) from the district centre Garmser, he said.

The military operation launched on April 28 is being led by US Marines and British military. The soldiers are searching compounds and trying to root out militants, destroy weapons caches and take positions held by the rebels.

There have been some clashes and air strikes, and military forces say they have killed "several" rebels although they have not released figures.

The United Nations has said it was ready to assist the affected people but it did not know how many had been displaced.

"We are concerned about this issue and the good thing about such displacements is that they are temporary and the people will be able to return to their homes soon," spokeswoman Nilab Mobarez told reporters.

Scores of families have already left the troubled area because of fighting over the past two years, with the Taliban storming in and holding it for a few days in July 2006 before being partially pushed back by NATO forces.

The military says Garmser is a rebel gateway into Afghanistan from neighbouring Pakistan, where extremist rebels are said to have bases.

The Taliban insurgency, launched after the rebels regrouped following their ouster from government in a US-led invasion in late 2001, is strongest in the areas bordering Pakistan but has made inroads into other areas.

In one of the latest incidents, an Afghan working on a road project was killed in an attack by Taliban fighters in the central province of Ghazni on Sunday, police said.

Police were sent to the area and a Taliban was killed and two policemen wounded in subsequent fighting, deputy provincial police chief Mohammad Zama said.