The aftermath of the bombing of the US Marines barracks in Beirut, Lebanon, in 1983. Photo: AP

Washington: The US Supreme Court has ruled that almost $US 2 billion ($2.56 billion) in frozen Iranian assets must be turned over to American families of people killed in the 1983 bombing of a US Marine Corps barracks in Beirut and other attacks blamed on Iran.

The court's 6-2 ruling on Wednesday dealt a setback to Iran's central bank, finding that the US Congress did not usurp the authority of American courts by passing a 2012 law stating that the frozen funds should go toward satisfying a $US2.65 billion judgment won by the families against Iran in US federal court in 2007.

The US Supreme Court building in Washington. Photo: AP

Bank Markazi had challenged a 2014 ruling by the New York-based 2nd US Circuit Court of Appeals that the assets, bonds held in a Citibank trust account in New York, should be handed over to the more than 1000 American plaintiffs.

Advertisement

Lawyers for the plaintiffs said the ruling resolved all the legal issues and they would now ask a federal judge to authorise distribution of money to the plaintiffs.

"We are extremely pleased with the Supreme Court's decision, which will bring long-overdue relief to more than 1000 victims of Iranian terrorism and their families, many of whom have waited decades for redress," said Ted Olson, a lawyer for the victims.

The aftermath of the 1996 Khobar Towers bombing at the King Abdul Aziz Air Base near Dhahran, Saudi Arabia. Nineteen US service personnel were killed in the attack. Photo: Getty Images

The plaintiffs have waged a long legal battle seeking compensation for attacks they say Iran orchestrated. Congress inserted itself into the dispute by passing the law to help the plaintiffs obtain the Iranian funds.

The plaintiffs accused Iran of providing material support to Hezbollah, the Iranian-backed Shiite Islamist political and military group responsible for the 1983 truck bomb attack at the Marine compound in Beirut that killed 241 US service members.

They also sought compensation related to other attacks including the 1996 Khobar Towers truck bombing in Saudi Arabia that killed 19 US service members.

The lead plaintiff is Deborah Peterson, whose brother, Marine Lance-Corporal James Knipple, died in the Beirut bombing.

The ruling, written by liberal Justice Ruth Bader Ginsburg, said the US Congress did not violate the separation of powers principle enshrined in the US Constitution giving specific authority to the government's executive, legislative and judicial branches.

In the past, the White House has objected to laws passed by Congress that it argues impede its conduct of foreign policy.

Ginsburg said the 2012 law  "does not transgress constraints placed on Congress and the president by the Constitution".

Chief Justice John Roberts, a conservative, criticised the ruling, saying he believes Congress was "commandeering the courts to make a political judgment look like a judicial one". Liberal Justice Sonia Sotomayor joined his dissent.

The plaintiffs are due to receive varying amounts of compensation depending on the size of the judgments they obtained in court against Iran. It was unclear how soon the funds will be distributed.

The ruling came during a delicate period in US-Iranian relations, following January's implementation of a landmark accord reached last year by the US and five other world powers to lift economic sanctions in exchange for Iran accepting limits on its nuclear program. 

Reuters