Prosecutors said the suspect, Mohammad Baqer Saad Dawood Al-Saadi, was a senior member of the Iran-backed militia Kata’ib ​Hezbollah and accused him of providing material support to a foreign terrorist organisation.

Al-Saadi ​is accused of coordinating or supporting nearly 20 attacks and attempted attacks across ⁠Europe and the United States, “including his efforts to kill on US soil,” said US ​Attorney Jay Clayton for the Southern District of New York in a statement.

The US government and ​independent experts say Kata’ib Hezbollah operates at the direction of Iran’s Islamic Revolutionary Guard Corps.

The charges come amid heightened US scrutiny of Iran-backed militias accused of targeting American personnel and allies across multiple regions amid ​the ongoing US and Israeli war against Iran.

US officials said he was taken into American ​custody overseas and transported to the United States, where he appeared before a magistrate judge and was ‌ordered detained ⁠pending trial.

ABC News reported he was detained in Turkey and handed over to the Americans.

Prosecutors allege Al-Saadi directed and encouraged attacks on US and Israeli targets as part of a broader campaign tied to Iranian-backed groups.

Defence ​attorney Andre Dalack declined ​to address the ⁠substance of the charges, saying it was too early to discuss details of the case.

But he cautioned against a “rush to judgment” and ​raised concerns about Al-Saadi’s detainment.

“We’re primarily concerned at the moment with ​the conditions ⁠of his confinement, as we understand he’s being held in solitary confinement, which we think is both cruel and unnecessary,” Dalack told Reuters.

Court documents cited by officials describe attacks linked to Al-Saadi ⁠and his ​associates that included bombings, arson and assaults targeting American ​interests abroad.

Officials also allege he discussed potential attacks inside the United States, including possible targets in New York, ​California and Arizona.