WASHINGTON - The Palestinian Authority and PLO cannot be sued under a 1991 US victim protection law over the alleged torture of an American in a West Bank prison, the Supreme Court ruled on Wednesday, holding that the law only applies to individuals.

The justices unanimously agreed with the Obama administration that the Torture Victim Protection Act allowed civil lawsuits in US courts only against a person who had engaged in torture or killing, not against groups.

The ruling involved a lawsuit against the Palestinian Liberation Organization and the Palestinian Authority by the widow and sons of a naturalized US citizen, the Palestinian-born Azzam Rahim, who was raised in the West Bank.

The lawsuit alleged he was tortured and killed in 1995 at a prison in Jericho while in the custody of Palestinian intelligence officers. The PLO has denied the allegations.

A US appeals court dismissed the lawsuit and ruled that the law adopted by Congress said that it only applied to individuals, not political groups or other organizations. The Supreme Court agreed.

"We hold that the term 'individual" as used in the act encompasses only natural persons. Consequently, the act does not impose liability against organizations," Justice Sonia Sotomayor wrote in the court's opinion. She added that Congress made that clear in the law's text.

Sotomayor said the ordinary, everyday meaning of individual referred to a human being, not an organization, and Congress gave no indication it intended anything different.

She said the arguments by those who brought the lawsuit were not persuasive. Their lawyers argued that precluding liability by organizations may foreclose effective remedies for victims and their relatives. But Sotomayor said Congress appeared well aware of the limits it had placed on the lawsuits.

In late February, the court heard arguments in the case and in a related case dealing with whether corporations or only individuals can be sued under a different US law, the Alien Tort Statute that dates to the 18th century.

The justices in March decided to hear arguments in their new term starting in October on a broader question in the other case - whether US courts even have jurisdiction to hear lawsuits against multinational corporations or others for alleged human rights abuses committed abroad.

The Supreme Court case is Mohamad v. Palestinian Authority, No. 11-88.