The recent claims by the Syrian opposition and the United Nations that Russia is using bunker-buster bombs in Aleppo would, if proven, confirm that a new, more destructive phase in the Russian assault on rebel forces is under way, and that the diplomatic track is effectively closed.



The bombs – capable of destroying underground shelters and command centres – would also suggest Russia is determined to bring the months-long siege of Aleppo to a speedy end, and that they have high-grade intelligence of the whereabouts of Syrian opposition positions.

Justin Bronk, research fellow at the defence thinktank RUSI, explained that bunker-busters are a very specific kind of destructive precision weaponry. “They show up as very different-shaped craters. They go very deep and explode deep underground so they tend to leave deeper but less wide craters than other bombs.”



He added it was very unlikely Russia would use such specific bombs at random or simply to blitz a city since they are very expensive and require specific targeting intelligence to be worth using. If they hit an underground shelter the number of deaths would be huge, but it would be much lower than other generalised heavy bombs if no specific target had been located.

He added it was quite possible Russia had acquired detailed information on the location of opposition headquarters. Both sides in the conflict are very aware the other is using underground tunnels to fight these quite static battles, and may have good intelligence of the other’s networks.

He added the most likely bomb being deployed was the laser-guided KAB-500L, analogous to the US Paveway series.

But the use of such destructive weaponry also creates a panic inside a city since civilian shelters, hospitals and medical centres, many located underground to avoid the government bombardment, are now vulnerable.

Conclusive proof that Russia is using bunker-busters may be hard to find, Bronk suggests, unless photographs of the craters or fragments of the shells are produced.

Charles Lister, an expert in Syrian opposition groups based at Washington’s Middle East Institute, has also posted pictures of what he claims to be an unexploded Russian BetAB-500 bunker-buster, adding he believes the weapon has been added to the Russian armoury. But the BetAB-500 is a lighter, rocket-propelled bomb more designed to destroy concrete structures and hardened structures such as runways.

In fact Russia has admitted to using these bombs in attacks in September last year against Islamic State command-and-control centres. The Russians said the bunker-busters targeted multilevel underground bunkers made of reinforced concrete.

Russia itself is rarely willing to discuss the weaponry it is deploying.

But the UN special envoy for Syria, Staffan de Mistura, at his briefing to the security council in New York on Sunday spoke unequivocally of a new armoury being deployed by the Russian air force, and identified bunker-buster bombs, saying they were increasing deaths, destroying already unstable buildings and leaving streets so full of rubble that rescuers could no longer reach bombed-out buildings in the city.

De Mistura told the security council: “We heard the words ‘unprecedented’, in quantity and also in scale and type, in the types of bombing. We have seen reports, videos and pictures of reported use of incendiary bombs that create fireballs of such intensity that they light up the pitch darkness in eastern Aleppo, as though it was actually daylight. We now hear of bunker-busting bombs being used and see pictures of large craters in the earth, much larger than in previous aerial bombings. If it is confirmed, the systematic, indiscriminate use of such weapons in areas where civilians and civilian infrastructure are present may amount to war crimes.”

An AFP photographer, Karam al-Masri, reporting from Aleppo for the past five years, said the destruction of the past few days was at an unprecedented scale. He told his AFP colleagues: “It is the first time that I’ve seen this level of destruction. What’s happening now is as destructive as all the bombing of the last three years,” he reported.

Syria Solidarity UK, a network of activists opposing President Bashar al-Assad, also claimed on the basis of conversations with the Aleppo council that the air assaults had not just multiplied, but changed in character: “The bunker-buster missiles used are causing massive shock waves; some buildings are collapsing without being targeted due to the effects of shock waves. These missiles are particularly designed to target underground shelters, so people have nowhere to hide. We woke up yesterday to a building that fell purely because of shock waves. Forty people died.”

De Mistura told the security council the UN no longer had the capacity to assess the scale of the Russian bombardment, but he said up to 275,000 people in eastern Aleppo were under a form of de facto siege for 20 days. Either way the change in the weaponry, combined with the collapse of the efforts to find a diplomatic solution following weeks of talks between the US secretary of state, John Kerry, and the Russian foreign minister, Sergey Lavrov, leaves the west without a clear strategy.

Boris Johnson, the UK foreign secretary, is due to hold talks in Ankara on Tuesday with Turkish government leaders, and will again be pressed to support the longstanding Turkish call for a no-fly zone over northern Syria. Johnson, who conceded at the weekend that the west had been too impotent on Syria, will also hear similar calls from the Syrian opposition based in Turkey. The UK ambassador to the UN, Matthew Rycroft, in an angry speech to the security council on Sunday night, said the issue for the west was no longer to urge and call, but to decide “what can we do to enforce an immediate end to the bombardment of Aleppo and other civilian areas in Syria? We must decide what we can do now to end the sieges, to end the chokehold that is preventing aid getting in.”