A hacking group "associated with the government of Iran" is launching disruptive-style cyberattacks according to a cybersecurity alert published by the US Homeland Security Department on Wednesday.

The attacks have targeted American companies, including healthcare providers and transportation companies.

CISA, the Federal Bureau of Investigation (FBI), the Australian Cyber Security Centre (ACSC), and the United Kingdom’s National Cyber Security Centre (NCSC) have released a joint Cybersecurity Advisory highlighting ongoing malicious cyber activity” by a group that FBI, CISA, ACSC, and NCSC assess is associated with the government of Iran.

“FBI, CISA, ACSC, and NCSC urge critical infrastructure organizations to apply the recommendations listed in the advisory to mitigate risk of compromise from Iranian government-sponsored cyber actors,” the statement by Cybersecurity and Infrastructure Security Agency has said.

Iranian hacking groups linked with the government of the Islamic Republic are among the world’s top cybersecurity threats, especially in targeting US, Israeli and European targets.