US federal court system websites were hacked Friday, blocking public access and preventing the filing of legal documents online. The intrusion impacted uscourts.gov, the main federal court website, as well as the government’s electronic filing system and its access page, PACER, a spokesman for the Administrative Office of the US Courts said Friday, RT reported. The federal court system, which manages its own cybersecurity, is investigating what occurred, the spokesman said, adding that the incident was a denial-of-service attack. It is not yet known who was responsible.