Beijing is to investigate complaints that Chinese-made weapons have turned up in the hands of Taliban insurgents fighting British and American troops in Afghanistan.

The investigation follows a UK Foreign Office claim that advanced anti-aircraft missiles, components for armour-piercing roadside bombs and land mines made recently in China's military factories have been recovered after clashes with the hard-line insurgents.

A Chinese foreign ministry spokesman said his government would "investigate fully" the concerns expressed by Britain, but insisted China's arms exports were carried out "in strict accordance with with our law and international obligations".

A British military source said the most alarming development was the discovery of shoulder-fired HN-5 missiles designed to circumvent normal decoy measures used by Nato helicopters and transport aircraft against heat-seeking weapons.

Shaped-charge bombs similar to those use to inflict casualties on coalition vehicle patrols in Iraq had also been recovered in Helmand and Kandahar provinces.

The high-velocity booby-traps are capable of penetrating even tank armour.

The source added: "There have been several recent attempts to shoot down Nato and US aircraft.

"They narrowly failed . . . but our luck cannot hold forever."

In Afghanistan yesterday, security forces said they had killed a Taliban commander involved in the kidnapping of South Korean church workers, less than a week after the captives were released.

Mullah Mateen was killed along with 16 other militants in clashes in Ghazni province, where the rebels seized 23 South Koreans on July 19.