WASHINGTON (AFP) - A journalist also known as an informal spokesman for the hacker group Anonymous was sentenced to five years in prison on Thursday in a case which rallied activists for press freedom, his supporters said.

Barrett Brown, arrested in 2012, was originally charged with collaborating with hackers but later pleaded guilty to lesser charges including accessory to the unauthorised access of a protected computer.

"United States of Injustice: Barrett Brown sentenced to 63 months in federal prison," said a tweet from the group "Free Barrett Brown" after the sentencing in federal court in Dallas, Texas.

Brown was also ordered to pay US$890,000 (S$1.2 million) in restitution.

Brown, who had written for Vanity Fair, Huffington Post and other news outlets, became an advocate for Anonymous and was indicted after posting links to data stolen from the security firm Stratfor Global Intelligence in 2011.

Brown's defence was supported by media rights organisations including the Committee to Protect Journalists and Reporters Without Borders, which claimed he was prosecuted for his actions as a journalist.

In his statement written for the hearing, Brown said "the government exposed me to decades of prison time for copying and pasting a link to a publicly available file that other journalists were also linking to without being prosecuted."

Brown and his supporters had asked him to be sentenced to time already served, or 30 months.