BANGKOK, July 9. /TASS/. The US decision to deliver cluster munitions to Ukraine will mark a serious escalation of the conflict, Thai columnist Tulsathit Taptim has said.

"America’s ‘difficult’ decision to provide Ukraine with cluster munitions marks a major escalation of a war that has already been very controversial and tipped by some to become far bigger," the columnist wrote in an opinion piece for Thai PBS.

"The US government used to be opposed to arming Ukraine with cluster munitions, as those in Washington joined much of the world in considering them indiscriminate weapons that cause harm to civilians," he added.

On July 7, US National Security Adviser Jake Sullivan said that the United States has decided to send Ukraine cluster munitions, even as the United Nations opposes the use of them. He also said that Kiev has provided Washington with written assurances that those weapons will be used in a way that minimizes risks to civilians. Pentagon Spokesman Patrick Ryder said on Thursday that the United States is poised to provide Ukraine with cluster munitions that pose the least risk to civilians.

A cluster bomb, or a cluster munition, can contain hundreds of explosive submunitions. When a cluster munition detonates in the air, submunitions can be left scattered on an area of tens of square meters. If some of them fail to function immediately but land on the ground without exploding, these submunitions pose a threat to civilians long after a conflict has ended. The 2008 Convention on Cluster Munitions has been joined by 111 countries so far, while another 12 nations have signed but not yet ratified it.