The US on Tuesday announced sanctions on two companies and four people linked to Iran's Islamic Revolutionary Guard Corps' cyber unit.
Mehrsam Andisheh Saz Nikp (Masn), Dadeh Afzar Arman and others have been accused of acting as fronts for campaigns launched on behalf of the IRGC's cyber unit.
Masn is also alleged to have been involved in a multiyear campaign against the Treasury and other US government agencies, as well as companies, the department said.
“Iranian malicious cyber actors continue to target US companies and government entities in a co-ordinated, multipronged campaign intended to destabilise our critical infrastructure and cause harm to our citizens,” Brian Nelson, undersecretary of the Treasury, said in a statement.
State Department spokesman Matthew Miller said in a statement that the US “will not tolerate malicious cyber activities victimising US companies”.
The US Department of Justice and the FBI also charged the four sanctioned Iranians over their alleged involvement in a lengthy cyber campaign against US companies.
The sanctioned people are accused of attacking the State Department, defence contractors and two companies in New York.
Tuesday's sanctions are the latest announced by Washington against Iran and its allies over malign and destabilising activity in the Middle East, as well as support for Russia's invasion of Ukraine.
Last week, the US and UK announced a sweeping set of sanctions against Tehran's drone programme after Iran's retaliatory missile and drone attack against Israel this month.
Tehran blamed Israel for an attack on an Iranian consulate building in Damascus on April 1 that killed 13 people, including Brig Gen Mohammad Reza Zahedi, a senior commander in the IRGC's Quds Force.
