Iran’s state-run IRNA news agency, in reporting the decision, offered no direct evidence to support the court’s allegation that American officials had any part in the June 2017 attack that killed at least 18 people and wounded 50 others. The assault saw gunmen attack Ayatollah Ruhollah Khomeini’s mausoleum and
the country’s parliament, starting an hours-long siege.

However, the court ruling comes after the United Nations’ highest court in March rejected Tehran’s legal bid to free up some $2 billion in Iranian Central Bank assets frozen by US authorities. Meanwhile, US judges have issued rulings that call for billions of dollars to be paid by Iran over attacks linked to Tehran, as well as those detained by Iran and used as pawns in negotiations between the countries.

The US State Department did not immediately respond to a request for comment Wednesday.

The IRNA report described those named in the lawsuit as including the US government, former Presidents George W. Bush and Barack Obama, the CIA, the
American military’s Central Command, the Treasury and others. It said the case before Branch 55 of the Tehran Court of Justice came from the families of three people killed in the June 2017 attack.

“The reasons for attributing these crimes to the United States ... is based on the central and main role of the government and officials of this country in organizing and directing terrorist groups,” the IRNA report said. It cited “reliable news” and unidentified speeches by American officials as its evidence.

During his 2016 presidential campaign, Donald Trump described Obama as the “founder” of the Daesh group. While later calling his comments “sarcasm” based on Obama’s decision to earlier withdraw troops from Iraq, conspiracy theorists across the Middle East, including Iran’s supreme leader, seized on the remarks.

The Daesh group, an extremist group born out of Al-Qaeda’s offshoot in Iraq, declared itself a caliphate across the vast territory it held in Iraq and Syria in 2014. A US-led coalition and separately Iran-allied Shiite forces ultimately dislodged the extremists, who became notorious for their gruesome killings of prisoners and attacks abroad.

The June 2017 attack in Tehran marked the first time the Daesh extremists could penetrate tightly controlled Iran and carry out of a massive assault. The assault shocked Tehran, which largely has avoided militant attacks in the decades after the years-long tumult surrounding the 1979 Islamic Revolution. Iran a year later executed eight men sentenced to death over the attack.

Since the revolution, a series of US court cases have been filed against Iran, particularly over attacks like the 1983 bombing of the US Embassy in Beirut that killed 63 people. A 1996 US law allows Americans to sue nations identified by the US government as sponsoring terrorism, like Iran, for damages suffered in militant acts linked back to them. Others have sued for being wrongfully imprisoned by Tehran, like Washington Post journalist Jason Rezaian.

The court decision announced Wednesday comes as tensions between Iran and the US remain high over Tehran’s nuclear program enriching uranium closer than ever to weapons-grade levels under reduced oversight from international inspectors.