A US federal judge has ordered Iran to pay $2.65bn (£1.3bn) to the families of 241 marines killed in a 1983 bombing of their Beirut barracks.
Iran denies responsibility for the 1983 bombing
The ruling allows nearly 1,000 family members and survivors to try to claim Iranian assets from around the world.
But getting the money will be difficult and the families are backing a law in Congress that would make it easier for victims to claim such compensation.
Iran denies involvement in the bombing and did not respond to the lawsuit.
'Sense of victory'
"This is a sense of victory, of winning a battle," said Paul Rivers, who was a 20-year-old marine on the second floor of the barracks when it exploded.
"When we win is when we collect, when we make them pay for what they did," he said.
US District Judge Royce C Lamberth called the ruling the largest such judgement by a US court against another country.
It is the result of a six-year lawsuit brought by family members of the dead marines as well as those wounded in the 23 October 1983 attack, which was blamed on the militant Islamic group Hezbollah.
An explosives-laden truck disguised as a water delivery vehicle rammed through protective barricades at the entrance of the compound and detonated in front of the barracks, demolishing the building and killing more than 300 people.
The blasts led to the withdrawal of the international peacekeeping force from Lebanon.
The Iranian government was accused of providing material and technical support to Hezbollah.