Claims that Vietnam has used defoliants to destroy Cambodian farmers’ crops will be taken to a global chemical weapons watchdog today on behalf of several Cambodian rights groups who say the alleged action violates international law.

A copy of the complaint scheduled to be filed with the Hague-based Organization for the Prohibition of Chemical Weapons (OPCW), which was obtained yesterday, cites the “unlawful use by the Government of Vietnam of prohibited chemical and biological weapons to defoliate and destroy food crops in contested border communities of Cambodia for the purpose of forced and unlawful land evictions”.

In April and May, it says, “Vietnamese operatives, including members of the Vietnamese military . . . engaged in the widespread spraying of chemicals on crops being grown” on disputed land in Tbong Khmum province.

It adds that similar incidents have been reported in disputed border land in Kampong Cham and Kratie provinces, and claims that the Cambodian government may have “participated in and supported the unlawful use of chemical agents”.

The complaint is being filed by US lawyer Morton Sklar on behalf of a coalition of Cambodian-American human rights and democracy groups.

Sklar has previously filed complaints against Prime Minister Hun Sen to international courts.

Today’s complaint claims that Vietnam has “violate[d] the provisions of the Chemical Weapons Convention (CWC) of 1993, as well as other standards of international law”.

Farmers living near the disputed border areas yesterday welcomed the action.

Forty-seven-year-old Teuk Sek, from Tbong Khmum’s Choam commune, said he personally lost around 0.7 hectares of farmland “after Vietnamese authorities used a chemical spray to kill the crops”.

On April 19, when he went to tend to his rice paddy, Sek claims he instead saw a group of people spraying chemicals “with support from four of five armed Vietnamese soldiers”.

Another farmer, 47-year-old Ear Yann, said villagers are prevented from tending to their remaining crops.

Ou Oeun, deputy chief of Choam commune, echoed the villagers’ claims.

Opposition lawmakers have also supported the allegations.

Vietnamese officials and the Cambodian Foreign Ministry could not be reached yesterday.

The complaint, meanwhile, calls for a “full and independent investigation”, a halt to further spraying and compensation to the victims.