WASHINGTON — U.S. courts will not be the world forum for lawsuits brought by victims of human-rights abuses abroad who seek damages from multinational corporations or deposed tyrants, the Supreme Court declared Wednesday.

WASHINGTON — U.S. courts will not be the world forum for lawsuits brought by victims of human-rights abuses abroad who seek damages from multinational corporations or deposed tyrants, the Supreme Court declared Wednesday.

In a decision welcomed by corporate leaders and decried by human-rights activists, the justices said U.S. courts are limited mostly to deciding disputes over conduct that took place on American territory, not on foreign soil. By a 9-0 vote, the high court tossed out a closely watched lawsuit brought by Nigerians against Royal Dutch Petroleum for allegedly conspiring with the Nigerian regime in a campaign of rape, torture and murder in the oil-rich delta in the early 1990s.

This suit had become a test of whether American courts could serve as a judicial forum for victims of gross violations of international law. The Supreme Court has cast a skeptical eye on these far-ranging lawsuits, and Chief Justice John G. Roberts Jr. announced an opinion Wednesday that will close the U.S. courts to most of them.

He invoked a legal doctrine known as the "presumption against extra-territorial application."

It means that unless Congress clearly says otherwise, it is understood that U.S. law "governs domestically, but does not rule the world," Roberts said.

Explaining the opinion from the bench, the chief justice said most of these human-rights claims, including the Nigerian suit, involve "foreign plaintiffs suing foreign defendants for conduct that took place on foreign soil."

Allowing Dutch oil companies or British mining firms to be sued in U.S. courts could cause foreign policy problems, Roberts said.

Moreover, U.S. citizens and U.S. firms could face suits in foreign courts for alleged abuses if such a wide-ranging jurisdiction were upheld, he said.

In the Nigerian case, the plaintiffs alleged that Royal Shell worked with the Nigerian regime to violently put down protesters who objected to oil exploration in Ogoniland in southeast Nigeria. They said the Nigerian military and police attacked, beat, raped and killed villagers and did so with the help of supplies and transportation provided by Royal Dutch.

But the chief justice stressed that "all the relevant conduct took place outside of the United States," and that is reason enough for tossing out the claim. Justices Antonin Scalia, Anthony M. Kennedy, Clarence Thomas and Samuel A. Alito Jr. joined his opinion in Kiobel vs. Royal Dutch.

Lawyers differed on whether the court's decision would end most or all of these international claims. Los Angeles lawyer Paul Hoffman, who represented the Nigerian plaintiffs, said he was "deeply disappointed" in the outcome, but said the court had "left open" the possibility that similar lawsuits can proceed in a state court. Kennedy noted in a separate opinion that the Torture Victim Protection Act of 1991 allows suits against officials who commit acts of torture abroad.

The four liberal justices agreed that a multinational company could not be sued in the United States simply because it had an office here. But they said the courts should be open to hearing lawsuits against deposed tyrants or other foreign officials who choose to reside in the United States.

Marcos, who fled the Philippines and settled in Hawaii, was one such example, noted Justice Stephen G. Breyer. Allowing suits here against deposed tyrants "vindicates our nation's interest in not providing a safe harbor, free of damages claims," for those who have committed grave human rights abuses, he said.

The ruling was several years in the making. Two years ago, the justices took up the Nigerian case to decide whether corporations should be shielded from claims of "aiding and abetting" abuses abroad. But after hearing arguments, the conservative justices said they wanted to consider a broader decision that would block these international claims. Wednesday's decision does just that.

Michael Bochenek, a director of Amnesty International, called the court's ruling a "startling reversal of years of progress toward ensuring that those who commit or are complicit in the worst abuses are not beyond the reach of the law because of where they operate."

Elisa Massimino, president of Human Rights First, said the decision had "severely limited a law that has been a beacon of hope for victims of gross human rights violations."

Business leaders here and around the world have urged the Supreme Court to rein in the law. They said corporations increasingly found themselves targeted for abuses perpetrated by Third World regimes.

"After many years of sounding the alarm against abuse of the ATS, we are extremely gratified that the court has handed down such a clear and well-reasoned ruling," said Peter Robinson, president of the U.S. Council for International Business.

Washington attorney Andrew Pincus, who defended companies against such suits, described them as "unjustified claims filed by plaintiffs' lawyers using the banner of 'human rights' to inflict huge litigation costs and brand damage on innocent companies." Rather than sue the foreign governments or foreign officials that abused their citizens, these lawsuits were "an attempt to coerce a settlement payment regardless of the merits of the claim," he said.