Mark Hertling was commanding a squadron of armoured vehicles in Iraq when he heard a series of loud pops overhead. It was five cluster bombs, of the same kind that the US last week authorised to be sent to Ukraine.
“It was like we were inside a popcorn popper, with small bomblets landing around us,” the now retired US lieutenant colonel recalled of that dread moment in 1991. Hertling, who was awarded a Purple Heart medal, extracted his men, 30 of them wounded, and believes his unit was caught in friendly fire during Operation Desert Storm.
The incident highlighted the destructive power of cluster bombs, or dual-purpose improved conventional munitions as these US variants are called, even when they do not fall into the wrong hands.
Fired from howitzers or rocket launchers, DPICMs drop small grenades, or bomblets, over a wide area where they can remain unexploded for decades after the conflict ends. That deadly legacy, and the devastating effect it has had on civilians, is why many countries now shun them.
These “area effects” also make DPICMs a formidable weapon in high-intensity, artillery-based conflicts, as in Ukraine, and can give Kyiv a timely boost at a time when its counteroffensive is stuttering against Russian forces’ well-built defensive lines, and Ukrainian troops are running low of conventional artillery shells.
Ukraine has said shortages have limited its troops to firing 100,000 rounds a month, a quarter of what the Russians are using and almost a sixth of the number of shells Kyiv has said its troops could fire. The US has an estimated 3mn DPICM rounds stored in US and allied bases in Europe.
“We want to make sure that the Ukrainians have sufficient artillery to keep them in the fight,” Colin Kahl, US under-secretary of defence for policy, said last week. “This is to make sure that the Ukrainians . . . have what they need, but frankly, also that the Russians know that the Ukrainians are going to stay in the game.”
Each DPICM can release up to 88 bomblets over an area the size of a football field, making them particularly effective against troops and artillery in the open.
They also provide suppressive fire that stops the enemy using their own weapons, which could help Ukrainian sappers as they clear the dense mine fields protecting Russian defensive lines, military analysts said.
“Ukraine’s forces need to create gaps in the Russian defences, so they can push through with armoured formations,” said Ben Hodges, a former commander of US armed forces in Europe.
Cluster munitions have a dark history. They entered mass production during the cold war, when they were designed for the large-scale bombardment of Soviet tanks and infantry formations.
But they have also been used indiscriminately against civilians. They were used during the Spanish civil war in Republican territory at Guernica, and again in the second world war when German planes dropped SD-2 “butterfly bombs” on Britain.
In the following decades, the US deployed them in Vietnam and in Laos, the UK in its battle for the Falkland Islands against Argentina and Serbia against Croatia.
One of their most heinous deployments came in 2006 in southern Lebanon when Israel is believed to have deployed more than 2mn submunitions. In 60 per cent of cases, those bombs hit residential areas, according to research by Landmine Action.
Their use during that conflict helped build momentum for a 2008 convention to ban these weapons, ratified by 111 states but not Russia, Ukraine, the US and several Nato members.
“Cluster munitions are a highly indiscriminate weapon,” said Anna Macdonald, former head of arms control at Oxfam, and a leading campaigner behind the convention. “It’s a weapon that has been widely derided, including by military experts.”
Military officials and analysts admit that DPICMs can be less effective against troops dug into deep trenches. But they have more of an impact in such cases than conventional shells, according to a paper published by the Royal United Services Institute, which argues for their use in Ukraine.
The failure rate of US-made cluster bombs is 2.4 per cent, compared with 30-40 per cent for Russian models, according to US defence officials.
Unexploded bomblets can also be a threat to friendly troops seeking to manoeuvre in areas where they have been fired.
Hodges, who was a brigade commander during the 2003 invasion of Iraq, recalls how one airfield that he was tasked with seizing was bombed by US cluster munitions. “Thankfully, in the end, we didn’t have to go in,” he said.
Despite these drawbacks, military officials and analysts said the advantages of DPICMs in Ukraine far outweigh their drawbacks.
For one, they point out that Kyiv is now fighting the very Russian formations that DPICMs were produced to fight against — and that Moscow has been deploying its own cluster bombs since it invaded Ukraine in 2022.
“Those wringing their hands about the US decision should ask themselves why Nato allies such as Estonia, Latvia, Poland, Finland and Romania haven’t signed the convention. It’s because these munitions work against Russian-style armies,” said John Foreman, the most recent UK defence attaché to Moscow.
Turkey has reportedly already supplied Ukraine with cluster munitions, and these have been used without any reported incidents of friendly fire, as suffered by Hertling during Desert Storm.
The danger of unexploded duds remains, but it pales next to the more than 10mn hectares of Ukrainian land contaminated by Russian mines and unexploded shells.
Ukraine has given written assurances to the Biden administration to use DPICMs strictly outside urban areas and to keep records of where the rounds were fired, prioritising those areas for demining. Kyiv will also report back to its allies about their effectiveness.
“It is important to note that the Russian Federation has been indiscriminately using cluster munitions from day one of the unprovoked large-scale aggression,” said Ukrainian defence minister Oleksiy Reznikov.
However, the clinching factor, officials and analysts said, was that the provision of DPICMs allowed Ukraine to continue its counteroffensive, minimise Ukrainian casualties and, ultimately, end the war sooner.
Moreover, if Kyiv’s allies had ramped up artillery shell production earlier and given Ukraine advanced weapon systems, such as fighter jets, there would be no pressing need for it to use DPICMs now.
“We need more systems and we need much more artillery ammunition,” said one Ukrainian military adviser. “Eventually Ukraine will win. The only question is how many of us die first.”
Additional reporting by James Politi in Washington