PESHAWAR: At least three suspected militants were killed in an 'accidental blast' at a Lashkar-i-Islam (LI) picket set up in Khyber tribal region's Tirah valley on Friday, sources said.

The explosion was followed by mortar shelling by security forces from Jarobi camp which led to the deaths of another four suspected militants.

Sources said the blast in Sandana area of Tirah valley's Sipah village occurred when explosives kept at the spot went off.

Soon after the explosion, other 'militants' rushed to the spot which was then targeted by security forces with artillery and mortar fire, resulting in the four deaths.

Security forces were still targeting militant positions from Jarobi camp near the Pak-Afghan border.

Khyber, one of Pakistan’s seven semi-autonomous regions governed by tribal laws, is situated near the Afghan border. The Taliban and other Al Qaeda-linked groups who stage attacks in both Pakistan and Afghanistan are also known to have strongholds in the zone.

The development comes amid Operation Khyber I which was launched in the region following intelligence on the presence of militants in parts of Sipah and Akkakhel areas.

The Mangal Bagh-led Lashkar-i-Islam has had a strong presence in the areas being targeted in this operation.

Anticipating a military operation in their areas in Tirah valley, hundreds of Akkakhel families left their homes in Dars Jumaat, Shaddaly, Darota and Kulla areas of Akkakhel in Tirah valley.

Khyber I was launched amidst 'Zarb-i-Azb', a full-fledged military operation being conducted by the Pakistani military against local and foreign militants in North Waziristan tribal region.