They posted messages vowing revenge for Washington’s killing of top military commander Qassem Suleimani.
The website of the Federal Depository Library Program was replaced on Saturday with a page titled “Iranian Hackers!”
The hackers uploaded a photo showing US President Donald Trump being punched by a fist emanating from Iran as missiles fly by.
“Martyrdom was (Suleimani’s), reward for years of implacable efforts”, they wrote.
“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,” it said.
“This is only small part of Iran’s cyber ability!” read another caption.
Iranian President Rouhani had vowed to revenge Suleimani’s death.
Cities across the Canada, Germany, United Kingdom and United States have witnessed protests over the killing of a top Iranian general Qassem Soleimani.
