Islamabad, Nov 24 (DPA) Pakistani forces killed at least 18 militants in an offensive launched Tuesday against the rebels believed to be behind a recent wave of suicide bombings in the north-western city of Peshawar, a security official said.

Hundreds of regular and paramilitary troops backed by helicopter gunships and artillery started the action early morning in the Khyber tribal district that adjoins Peshawar, capital of the restive North-West Frontier Province.

'The security forces killed 18 terrorists and apprehended six more, besides destroying 12 of their vehicles,' said Major Fazlur Rehman, spokesman for the paramilitary Frontier Corps.

Rehman said soldiers had seized an important Taliban base in Gurgure area. 'A large quantity of ammunition and weapons were recovered from there,' he told DPA by phone from Peshawar.

The Taliban were using the centre as a private jail to keep the people kidnapped for ransom. 'We recovered handcuffs and other torture instruments,' he added.

The operation in Khyber is mainly aimed at Lashkar-e-Islam, a militant group with close links to the Taliban. Authorities suspect the outfit is responsible for a string of suicide attacks in Peshawar that have killed over 225 people over the last seven weeks.

A suicide car bomber devastated a busy women's market late October, killing more than 110 people, mostly women and children.

On Nov 13, a bomber detonated his explosives-laden vehicle at the gates of the military's main Inter Services Intelligence agency, killing at least a dozen people.

Pakistani officials say these suicide bombings are part of a Taliban campaign to retaliate against the ongoing military assault in another tribal district, South Waziristan.

The Lashkar-e-Islam is also blamed for facilitating the Taliban attacks on trucks carrying supplies for the Western troops in Afghanistan.

The key land route used to ferry almost 75 percent of the fuel, food and military supplies to the US and NATO forces from Pakistan's main port in Karachi runs through the Khyber district.