A U.S. federal judge has ruled American chemical companies are not liable for damages caused by the spraying of Agent Orange during the Vietnam War.

Judge Jack Weinstein Thursday dismissed a lawsuit that accused the companies of committing war crimes by producing the highly toxic chemical.

The suit was filed on behalf of Vietnamese citizens who have blamed Agent Orange for health problems including cancer and birth defects.

U.S. forces sprayed some 80 million liters of the chemical during the war to kill jungle foliage that communist forces were using as cover.

Judge Weinstein said the plaintiffs' claims have no basis under any national or international laws.  He also said the plaintiffs had failed to prove a clear link between Agent Orange and their illnesses.

There was no immediate reaction from plaintiffs or the Vietnamese government.

Some information for this report provided by AP and AFP.