The International Court of Justice's ruling to permit Iran to proceed with a lawsuit to recover its frozen assets in the United States is an attempt by Tehran to misuse the court, the US Department of State said in a statement.
Judges rejected United States claims the case should be thrown out because Iran had "unclean hands" from alleged links to "terrorism", and the worldwide tribunal in The Hague did not have jurisdiction over the lawsuit.
The U.S. Supreme Court ruled in 2016 that the funds must be turned over to American families of victims of alleged Iranian terrorist attacks, including the 1983 bombing of a U.S. Marine barracks in Beirut, in which 241 soldiers were killed, and the 1996 Khobar Towers bombing in Saudi Arabia.
At hearings a year ago, the United States raised five objections to the court's jurisdiction and the admissibility of the case, which Iran filed in 2016.
Tehran filed the case in 2016 based on the 1955 Treaty of Amity between Iran and the USA, a bilateral agreement that Washington withdrew from previous year.
Service members pick through debris following the bombing attack at the U.S. Marine Corps barracks in Beirut, Lebanon, on October 23, 1983. It includes a clause that sends unresolved disputes about interpretation of the treaty to the world court.
The United States announced hours after that decision it was pulling out of the Treaty of Amity, upon which Iran had also based the sanctions case. Its rulings are binding and can not be appealed, but it has no means of enforcing them.
Tehran said the United States had illegally seized Iranian financial assets and those of Iranian companies.
The ruling rejected an argument by US officials that the court does not have the authority to make such a move. Tehran is seeking to regain funds that were impounded during the 1979 Islamic Revolution in Iran.
Relations have been strained ever since US President Donald Trump's decision previous year to pull out of a "terrible" worldwide nuclear deal with Iran and reimpose sanctions.
Iran first lodged the case on the frozen funds in June 2016, accusing Washington of breaking the decades-old bilateral treaty dating from the time of the US-backed shah, who was deposed in the revolution.
The lawsuit was filed with the United Nations high court at The Hague by Iranian officials on October 8.
In Poland this week, US Secretary of State Mike Pompeo will use a two-day conference of foreign ministers to try to rally the world behind increasing pressure on Iran and supporting Israel, although turnout could be thin.