Southeast Asian nations still struggling to clear cluster munitions dropped on them by U.S. forces during the Vietnam War are pleading with the Americans to back away from sending the deadly bombs to Ukraine.

In a rare statement posted online Monday by the Laotian Ministry of Foreign Affairs, the government called on unspecified states or actors from all use, transfer or production of such munitions "so that no one in the world would be victimized” by such weapons.

"As the world’s largest victim of cluster munitions and a state party to the Convention on Cluster Munitions, the Lao People’s Democratic Republic expresses its profound concern over the announcement and the possible use of cluster munitions,” the statement said.

Washington has said it will send cluster bombs to Ukraine as part of a new push to support the country’s counteroffensive and boost its dwindling stocks of ammunition, overruling concerns that the weapons often fail to explode and pose a grave danger to civilians.

U.S. President Joe Biden called the move to send cluster bombs to Ukraine a "difficult decision” given the risk to civilians posed by the weapons, but said Russia had been raining the munitions down on Ukraine for months.

Unexploded ordinances dating back half a century are still being discovered in Vietnam, Laos and Cambodia, after causing tens of thousands of deaths and injuries during and after the war. The U.S. has contributed more than $750 million in those countries for conventional weapons destruction over the last three decades.

"It would be the greatest danger for Ukrainians for many years or up to a hundred years if cluster bombs are used in Russian-occupied areas in the territory of Ukraine,” Cambodian Prime Minister Hun Sen tweeted on Sunday. "I appeal to the U.S. president as the supplier and the Ukrainian president as the recipient not to use cluster bombs in the war because the real victims will be Ukrainians.”