KANDAHAR (Afghanistan) - AFGHANISTAN'S insurgent Taleban movement said on Monday that they had launched a guerrilla operation to counter a major assault by US Marines on their stronghold in Helmand province.

Operation Foladi Jal, or 'iron net' in Pashtu, would teach the Marines 'a lesson,' Taleban spokesman Yousuf Ahmadi told AFP by telephone from an unknown location.

About 4,000 Marines poured into the southern province on the border with Pakistan in an operation called Khanjar (dagger) that has faced little resistance since it was launched five days ago.

'In response to Operation Khanjar by the invading forces, we have launched Operation Foladi Jal,' Ahmadi said.

'In this operation we'll teach them a lesson so they will never again dare to come into our areas,' he said, referring to the militants' long-time stronghold.

The operation would include improvised bomb explosions and 'hit-and-run guerrilla attacks.

The assault by Marines, along with about 600 Afghan forces, has pushed into several key towns in southern Helmand and aims to hold the areas to allow Afghans to vote in August 20 presidential elections.

One Marine has been killed but officials have not released casualty figures for the insurgents, adding that many seem to have gone to ground.

Officials have said the Taleban are unlikely to oppose directly such a massive insertion of Marines, but would instead resort to bombings, the main feature of their campaign against the government and its international allies.

The Taleban were in government between 1996 and 2001, until they were ousted by a US-led invasion for sheltering Al-Qaeda. -- AFP