The Thai government said yesterday that it disputes the description of weapons it used during border clashes with Cambodia in February as cluster bombs, an internationally condemned weapon.

On Wednesday, the Cluster Munitions Coalition said it had “conclusive” evidence that Thailand had deployed cluster munitions, which are banned by a 2008 treaty signed by 108 countries and ratified by 55, after two on-site investigations together with confirmation from the Thai ambassador to the United Nations in Geneva.

Neither Cambodia nor Thailand have signed the treaty, which entered into force in August.

Thai government spokesman Panitan Wattanayagorn said yesterday the Thai military had used 155-milimetre Dual Purpose Improved Conventional Munition in the clashes, but that the military does not consider the weapons to be cluster munitions. When questioned whether Thailand used cluster weapons during the conflict, he said: “The answer is, according to the military, no.”

The CMC disagrees.

Laura Cheeseman, director of the organisation, said the weapon “is most definitely a cluster munition.”

“Every country considers DPICM as cluster munitions,” she said in an email from London, and added that the weapons were defined as clusters in the 2008 Convention on Cluster Munitions and its draft protocol.

“It has the effects and impact of a cluster munition and has been well documented in several conflict[s] to cause harm to civilians during and after attacks,” she said, citing the wars in Afghanistan, Iraq, Lebanon and Georgia over the last decade.

Cluster munitions have been internationally condemned because of their long-term consequences for civilians.

The shells split open after they are launched, or dropped by air, scattering bomblets across a wide area. These bomblets often lie dormant for years before exploding, leaving a lasting threat.

Heng Rattana, director general of the Cambodian Mine Action Centre, said DPICM were “clearly” part of the cluster munitions ban.

Panitan said the military had used DPICM in retaliation for alleged Cambodian BM-21 rocket fire that hit Thai civilians, though he was not sure how many civilian casualties had occurred.

Heng Rattana said BM-21 were “conventional weapons”.