Islamabad, Sep 5 (Xinhua) Pakistani security forces demolished the headquarters of banned militant outfit Lashkar-e-Islam Saturday as a military operation against militants in the country's northwest entered its fifth day, media reports said.

Security forces pounded Tirah valley in Khyber tribal agency's Bara region, destroying the headquarters of Lashkar-e-Islam, Geo news reported. Four bodies were recovered from the area.

In a media briefing, the political agent of Khyber agency Tariq Hayat Khan said that 57 militants have been killed, 107 arrested and 54 hideouts destroyed in the ongoing operation.

He said that a large quantity of detonators, hand grenades, and explosives used in suicide jackets were recovered Friday, adding that the operation would continue till the restoration of peace in the area.

The operation was launched five days after a suicide attack Aug 27 in Khyber agency that killed 21 troops. Hundreds of regular army, paramilitary force, Frontier Corps and local tribal force are taking part in the offensive.

Khyber agency is located on a key supply route for NATO forces in Afghanistan and militants regularly target supply trucks in the region.