RAWALPINDI, Aug 20: High explosives weighing 5kg packed with nails and ball bearings were used in Thursday's suicide bombings outside Pakistan Ordnance Factories (POF) Wah, Dawn has learnt.

It was the same type of explosive that was used in the two suicide attacks in Rawalpindi on September 4 last year near Qasim Market and the GHQ.

An unexploded Russian-made hand grenade, believed to have been thrown by one of the bombers, was also found at the site of the attack in Wah which killed at least 64 people and injured scores others.

Bomb disposal experts defused the grenade and combed the surrounding area for more.

A joint investigation team comprising SIG, army experts and police visited the scene of the carnage. It collected pieces of the suicide vests and the explosives.

Security forces across the country have been placed on high alert following the twin suicide bombings in Wah.

Army night patrols were increased in the garrison city of Rawalpindi and police have started random checking of vehicles.