A global Internet hacker group has followed through on its threat to attack official websites in Malaysia in retaliation for the government's censorship practices.

Malaysia's communications regulator says 51 websites were targeted in the attacks, which began shortly before midnight Wednesday, causing disruptions to at least 41 of them. The regulator says most of the websites were back to normal by Thursday.

The group, which calls itself “Anonymous,” said it was punishing the government for blocking access to 10 or more file-sharing websites. It called the government's action a denial of basic human rights.

Malaysia says it blocked access to the websites because they facilitated the piracy of copyrighted material.

“Anonymous” gained prominence when it launched a cyberattack against financial transaction companies Visa, Mastercard and Paypal. The companies had cut off services to WikiLeaks after it began publishing secret U.S. diplomatic cables.

The group has attacked official websites in a number of countries, including Turkey. Authorities there arrested dozens of suspected hackers believed to have ties with “Anonymous.”