Kabul  -  Coalition forces killed at least 12 suspected Taliban militants during an operation in southern Afghanistan, where Afghan officials confirmed that thousands of residents have left their homes in fear of NATO airstrikes.

The militants were killed in Garmsir district of volatile southern Helmand province on Monday during a search operation by US-led coalition forces that targeted a Taliban commander, the US military said in a statement Tuesday.

The targeted commander was involved in conducting weapon supply operations in the area, it said.

The combined forces were fired at as they entered the area, the statement said, adding the joint troops responded "with small-arms fire and airstrikes."

Multiple rocket propelled grenade, machineguns, AK-47s, cases of ammunition and two mortars, were seized from the targeted house.

Meanwhile Afghan officials confirmed on Tuesday that thousands of residents in Garmsir district had left their houses in fear of airstrikes by international forces since the start of a NATO-led operation in the district on April 28.

International military airstrikes in the past have left dozens of civilians dead in southern Afghanistan when foreign forces bombarded the areas, where suspected militants were hiding.

Shamsuddin Sarhadi, spokesman for Afghan Ministry of Refugees and Repatriation said that around 900 families - accounting for more than 5,000 people - had left their homes in Garmsir district and most of them were now in a camp receiving assistance from the Afghan government and United Nations.

In order to contain the Taliban militants during the spring and summer, the two fighting seasons in the southern region, more than 3,500 US Marines were deployed in southern Afghanistan to assist the British and Canadian forces, who are based there as part of some 50,000 NATO-led troops in the area.

Since the start of operation, which is aimed to extend the Afghan government's influence in Garmsir district, the NATO forces comprised mainly of US and British soldiers have claimed several victories in their operations, in which scores of militants and their supporters were killed, while several weapons caches were discovered and destroyed.

In a separate incident, the US military said in a statement that one of their helicopters made a "hard landing" in north-east Nuristan province on Monday night.

The cause of the crash was being investigated, it said, adding that there were no casualties due to the crash.

Some 17 US service-members were killed in a helicopter crash in eastern Kunar province in June 2005. (dpa)