The reaction of the USA killing Ghassem Soleimani
did happen on saturday evening local time and the
Federal Depository Library Program (FDLP) website
had a clear statement visible instead of the usual page.

While the U.S. government was busy to remove the defacement as quick as possible, the Internet archive website was already able to take a snapshot of the defaced page:

Usually the page looks like this:

The Cybersecurity and Infrastructure Security Agency (CISA) confirmed the defacement and hacking attempt and clearly stated that no personal data was at risk as only the front page had been modified.

Although this is only a minor incident, the current political relationship between the USA and Iraq, Iran will not be very good at the moment and revenge has already been promised for the killing of Ghassem Soleimani.