Can hackers disable ITU's site?
Can hackers disable ITU's site?Israel news photo: Flash 90

Activists from the infamous hacker group known as Anonymous have disabled the United States Sentencing Commission's website and have vowed to release classified government information in revenge for the death of Internet freedom advocate Aaron Swartz.

The hackers replaced the website of the commission, an independent agency of the U.S. Justice Department involved in sentencing, with a video denouncing the government and praising the 26-year-old activist, who hanged himself two weeks ago as his trial date for allegedly hacking into a computer network neared.

Swartz, who was accused of illegally downloading academic articles from the Massachusetts Institute of Technology (MIT), faced up to 35 years in prison and a $1 million fine.

He had long promoted open access of information on the Web and had allegedly planned to distribute the information free of charge.

Swartz, who was found hanged in his New York apartment earlier this month, was just 14 years of age when he co-developed the RSS feeds that are now the norm for publishing updates online. He then went on to help launch social news website Reddit.

"As a result of the FBI's infiltration and entrapment tactics, several more of our brethren now face similar disproportionate persecution, the balance of their lives hanging on the severely skewed scales of a broken justice system," Anonymous said in a video posted on YouTube.

The hackers said they had infiltrated several U.S. government computer networks and could release secret data they had succeeded in copying.

Likening the data to a nuclear weapon, Anonymous said it had "enough fissile material for multiple warheads" it could launch against the Justice Department and agencies that the group says breach individual liberties.

The FBI’s Criminal, Cyber, Response Services branch put out a statement Saturday: “We were aware as soon as it happened and are handling it as a criminal investigation. We are always concerned when someone illegally accesses another person's or government agency's network.”

The Anonymous operation came just days after U.S. Homeland Security Secretary Janet Napolitano warned of a looming "cyber 9/11" that could especially target critical infrastructure planks such as water, electricity and gas lines.

The loosely affiliated network of hacktivists has attacked sites around the world, including those of MasterCard and Visa, the Justice Department and the Tunisian and Yemeni governments.