ISLAMABAD, Dec 5: Experts of the Federal Investigation Agency investigating the recent terrorist attack on the Abdullah Shah Ghazi shrine in Karachi believe that 'sophisticated military explosives', and not homemade material, were used in the blast, with a hand-grenade as a trigger.

According to sources, a report submitted to the government suggests that residues found at the place where the first explosion took place and on the roof of the shrine match those used in attacks on an Ahmadi centre in Lahore and some places in Peshawar, Tank and Swat. The report did not say how and in what quantity the terrorists got the sophisticated military explosives.

The experts said analysis of all the components collected from the site had the properties of RDX and TNT.

The RDX had been used in the attacks on Data Darbar and Karbala Gamay Shah in Lahore and on the US consulate in Peshawar in April. The same material was used in the Nishtar Park bombing in Karachi in 2006, attack on PML-Q leader Ameer Muqam and a major truck bomb attack on the Marriott Hotel in Islamabad in 2008.

Two explosions took place within a minute on Oct 7 at the shrine in Clifton area of Karachi, located at a distance of 1km from Bilawal House, leaving eight people dead and 70 injured.

The report said that a head and a torso with head, shoulders and both hands were found at the crime scene.

Ball-bearing pellets of 6mm diameter, parts of suicide belt, electronic circuits, explosive material and two striker sleeves were also found.

The residue swabs taken from the place were sent to FIA's explosives laboratory in Islamabad for examination.

The first blast took place at the entrance of the shrine where there was no crater but pellet marks on the ground and pillars of the gate about 20 feet away. A barrier about 40 feet away was also blown up.

The explosives were strapped around the waist of the bomber.

The report suggested that the terrorists had chosen the method of twin-bombings – the first to penetrate through the security and the second to hit the shrine. The first blast was of a lower intensity, bust caused more casualties.

It said the bombing appeared to be a continuation of the attack on Data Darbar.

The experts said that security arrangements should be tightened in view of the large area of Karachi and presence of a number of targets in the city.

They said the banned Tehrik-i-Taliban Pakistan (TTP) could have been involved in blasts because it had previously attacked sectarian targets and claimed responsibility.