The activist hacker group Anonymous attacked three Mexican government websites on Friday in protest at a proposed bill that seeks to toughen local laws about online file-sharing.

The affected sites belong to the Interior Ministry, the Senate and the Chamber of Deputies. The homepage of the Interior Ministry remained offline by mid-afternoon.

“We demand the Mexican government not continue with this law because they will take away our freedom of speech and file sharing,” Anonymous said in a video posted on Youtube ahead of Friday’s action.

The proposed law, floated last month by a senator from the ruling National Action Party, Federico Doring, would criminalize the uploading of music, videos or books to the Internet without the permission of copyright holders.

Anonymous members and their supporters took to Twitter to coordinate the attacks under the hashtag “OpDoring” with messages including “Senate TANGO DOWN !! FIREEE don’t hesitate to shoot” and “Change of target deputies ... FIRE.”

Interior Minister Alejandro Poire confirmed his ministry’s website had been hit by a denial-of-service attack. He said the government was working to prevent such strikes, and that it would investigate and prosecute any crimes committed.

“We will certainly verify the security protocols of the ministry’s website to ensure the integrity of its information and prevent future attacks,” he said.

Anonymous, a loosely knit group that has attacked financial and government websites around the world, compared Doring’s proposal with anti-piracy bills in the United States that were halted after a huge online protest this month.

The hacker group had clashed with Mexican officials before. Anonymous claimed responsibility in September after the websites of several Mexican government ministries, including Defense and Public Security, went offline.