What are cluster munitions? Why the bombs are banned as Russia accused of using weapons in Ukraine

Russia has been accused by humanitarian groups of using cluster munitions during its invasion of Ukraine.

Amnesty International condemned the reported use of such weapons, saying that an attack on a Ukrainian nursery “may constitute a war crime”.

For more than a decade, a convention backed by more than 100 countries has banned the use of cluster munitions – however, neither Russia nor Ukraine are among the agreement’s signatories.

Here’s what you need to know about the weapons, and what Russia has been accused of doing during its war with Ukraine.

Cluster munitions are weapons that scatter or release smaller munitions or bomblets over a wide area, increasing the potential for casualties and damage.

As defined by the Convention of Cluster Munitions, the term denotes: “A conventional munition that is designed to disperse or release explosive submunitions each weighing less than 20 kilograms, and includes those explosive submunitions.”

It does not apply to munitions that disperse flares, smoke or pyrotechnics, or weapons designed exclusively for aerial defence.

Human Rights Watch says: “Cluster munitions pose an immediate threat to civilians during conflict by randomly scattering submunitions or bomblets over a wide area.

“They continue to pose a threat post-conflict by leaving remnants, including submunitions that fail to explode upon impact becoming de facto landmines.”

More than 100 countries have committed never to use the weapons under the Convention on Cluster Munitions, which came into effect in August 2010.

The likes of the UK, Germany and France are among the nations that have backed the agreement signatories, but it has not been signed by Russia, Ukraine, Israel or the United States.

Amnesty International said “a 220mm Uragan rocket dropped cluster munitions on the Sonechko nursery and kindergarten in the town of Okhtyrka in Sumy Oblast” on Friday.

The human rights charity added that the attack left three people dead, including a child, while another child was wounded. It added: “The strike may constitute a war crime.”

Human Rights Watch also said it had identified use of cluster munitions, stating that Russia deplyed a bomb in the town of Vuhledar. It said that the attack killed four civilians.

Bellingcat, a website specialising in investigations and verification, said on Sunday that it had located multiple sites in Ukraine where cluster munitions had been used.

It outlined two, at a pre-school in the city of Okhtyrka, and in Kharkiv, where it had verified social media reports of cluster munition attacks.

Bellingcat said: “Open source evidence from Ukraine appears to suggest that the cluster munitions… are not being carefully targeted. Instead, we have identified multiple examples that have impacted civilians, schools and hospitals.

“As the fighting begins to move further into urban areas, there is a danger there could be significantly more examples of such usage of cluster munitions.”

Dr Agnès Callamard, secretary-general of Amnesty International, said: “It is stomach-turning to see an indiscriminate attack on a nursery and kindergarten where civilians are seeking safe haven. Plain and simple, this should be investigated as a war crime.

“As this human tragedy unfolds in Ukraine, any person who commits war crimes should be held individually accountable before the International Criminal Court (ICC) or another international criminal justice process at the national or international level.

“It is imperative that UN member states and the ICC urgently consider how to ensure the timely and effective collection and preservation of evidence of any crimes under international law committed in Ukraine.”

Additional reporting from Press Association