Afghan and foreign forces have killed at least 60 opposition fighters and destroyed 92 tonnes of drugs.

The moves on the opposition hub on Saturday ended a four-day operation in the southern Helmand province, the military said on Saturday.

"A total of 60 militants were eliminated as they mounted an ineffective and uncoordinated defence against friendly forces," a joint US and Afghan military statement said, giving a final tally for the whole operation.

The drugs seizure in Marija, southwest of Lashkar Gah, the provincial capital, was "the single-largest drug cache by Afghan-led forces in Afghanistan to date", according to the statement.

'Key hub'

Opium poppy seeds, processed morphine and heroin, hashish, bomb-making materials and chemicals were all found and destroyed.

The haul was subsequently destroyed by a precision air raid.

The attack "severely disrupted one of the key militant and criminal operations and narcotics hubs in southern Afghanistan," the statement said.

Helmand, a Taliban stronghold, is the main producer of Afghan opium, which makes up more than 90 per cent of the world's supply.

International authorities have repeatedly warned of the links between drug production in the region, which they say accounts for millions of dollars in revenue each year, and opposition groups.

In a separate incident early on Saturday, Taliban fighters fired a rocket at a civilian mini van in the Ghazni province in central Afghanistan, killing two people.

The Taliban have taken back large parts of southern Afghanistan in the past few years after being ousted by US-led forces after five years of rule in 2001.

International forces entered the country after asserting that the Taliban were harbouring al-Qaeda members following the September 11 attacks on the US.