In what may well be the first sign of retaliation for the assassination of Iranian general Quassem Suleimani by a U.S. drone strike in Iraq, a group of hackers who claim to be from Iran gained access to a federal website and posted messages threatening “severe revenge” on President Donald Trump for the killing of Suleimani.

The Guardian reports:

“The website of the Federal Depository Library Program was replaced on Saturday with a page titled “Iranian Hackers!” that displayed images of Iran’s supreme leader Ayatollah Ali Khamenei and the Iranian flag.”

The image and text posted on the hacked U.S. government website

Along with the image of Trump being punched in the face was this message:

“Martyrdom was (Suleimani’s)… reward for years of implacable efforts.

“With his departure and with God’s power, his work and path will not cease and severe revenge awaits those criminals who have tainted their filthy hands with his blood and blood of the other martyrs.”

Another caption on the hacked website read:

“This is only small part of Iran’s cyber ability.”

The hacker of the site claimed to be the “Iran Cyber Security Group Hackers.”

Iran is believed to have one of the most extensive and advanced cyber warfare programs in the world, according to the Washington Post:

Cybersecurity expert James A. Lewis recently compiled a list of suspected Iranian hacks, cyberattacks and online spying incidents and was surprised to find 14 reported last year alone. The list included hacks aimed at the Trump campaign, telecommunications systems in Iraq, Pakistan and Tajikistan, and intrusions into employee accounts of companies making and operating industrial control systems. Iranians also reportedly used LinkedIn to target users affiliated with Middle Eastern governments and workers within the financial and energy industries.

“They have enough capability that they don’t need to ask, ‘Can we do this?’ ” said Lewis, a senior vice president for the Center for Strategic and International Studies. “It’s, ‘Do you want to do this?’”

Iran also has ties to terrorist groups across the globe and may send out orders for increased terror activity in the days ahead.

Featured Image Via Screenshot