Israelis to unleash 'bunker busters' in hunt for Nasrallah

The Israeli Defence Forces' (IDF) pattern of air and ground attacks on civilian targets - including indiscriminate attacks on women and children in vehicles moving north, away from the border or in close proximity to known hospitals - suggests it has created a "free-fire" zone in southern Lebanon.

Meanwhile, Hizbullah's ability to operate appears undiminished. On the ground, Hizbullah fighters appear to have been able to make an orderly withdrawal from the border village of Maroun al-Ras following a much-publicised Israeli assault - carried out by an elite paratroop unit of the IDF. Hizbullah also continues to fire rockets into Israel, apparently at will.

In a renewed and concerted attempt to remove the leadership of Hizbullah, Israel has accelerated its programme to acquire 100 GBU-28 specialised "bunker-buster" bombs from the US. In an attempt to "decapitate" Hizbullah, Israel plans to kill Hassan Nasrallah using the US manufactured GBU-28 (Guided Bomb Unit 28). This laser-guided "smart" munition is especially designed to penetrate and destroy "hard and deeply buried targets" (HDBTs) or underground bunkers of the type that Nasrallah and his Hizbullah leadership are believed to be sheltering in - somewhere in Beirut.

The GBU-28 missile weighs more than 1000kg and can be fired by Israeli F-16 fighter jets. It has a warhead consisting of 300kg of Tritonal high explosives detonated by the "super penetrator" BLU-113 hard target smart fuse (HTSF). In layman's terms, the HTSF allows the missile to "burrow" through 10 metres of reinforced steel and concrete or 100 metres of packed earth to detonate deep within a "missile-proof" or buried enemy structure.

The Tritonal high explosive charge is shaped to detonate and create a high-pressure explosive wave that can navigate subterranean shelters and their complexes of tunnels and ante-chambers, shattering, burning and killing all inside.

Despite such frightening technology, the successful deployment of this weapon relies on good, hard, timely intelligence and the laser or GPS identification of the correct target. In Beirut's tangle of back streets, alleyways and bomb-damaged rubble it will be difficult to correctly identify Nasrallah's bunker. If the IDF - in this densely populated urban environment - mistakenly hits a building filled with innocent civilians, the consequences would be unthinkable.

Despite the shock and awe implied in the military designations "bunker buster" or "super penetrator", the imminent attempt to kill Nasrallah with a GBU-28 resembles more a hunt for a needle in a haystack than a precise surgical strike. This would appear all the more so in the context of an indiscriminate and inconclusive IDF air and ground campaign.

•Tom Clonan is The Irish Times' security analyst.