The Central Bank of Iran (CBI) was reportedly hit by a cyberattack on Wednesday, along with several other banks in the country, causing chaos in the Iranian financial system.

According to a report by Iran International, the scale and impact of the attack indicate that it is one of the largest cyberattacks that Iran’s state infrastructure has ever experienced. Hackers are also believed to have stolen information from account holders.

There were notes stuck on ATMs by anonymous people reading: “Dear customers, it is not possible to withdraw money from the bank, because the entire budget and national resources of Iran are invested in the war for the benefit of the corrupt regime of the Islamic Republic.”

The alleged cyberattack comes at a time of heightened tension as Iran’s Supreme Leader Ayatollah Khamenei threatens to take revenge for the killing of Hamas leader Ismail Haniyeh. The disruption also comes after reports suggesting that Iranian hacker involvement in influencing the upcoming US elections.