At least 41 Malaysian government websites were hacked into overnight but no personal or financial data were compromised, government officials said on Thursday, as the Southeast Asian nation becomes the latest target of a cyber-war waged by the activists.

In the attacks, 51 websites were hit and at least 41 of these sites were disrupted, industry regulator Malaysian Communications and Multimedia Commission said.

The attacks, which began shortly before midnight on Wednesday, follow a warning by Internet vigilante group Anonymous, which said it would attack the government's official portal to punish it for censoring WikiLeaks, the website that aims to expose governments and corporations by leaking secret documents.

Our monitoring of the situation showed that there was a reduced level of attacks by 4.00 a.m. this morning and upon further evaluation, so far, we gauge that there has been little impact on Malaysian users as a result, the communications commission said in a statement.

It did not name the sites which were attacked but targets included the government's online portal, and the webpages of the fire and emergency services department and the land public transport commission.

Malaysian police chief Ismail Omar told Reuters no personal or financial data had so far been stolen but the authorities were trying to determine the extent of the attacks.

It was not immediately clear if the attacks were launched by Anonymous or other hackers.

Anonymous is a grouping of global activists lobbying for Internet freedom who frequently try to shut down the websites of businesses and other organisations that they oppose.

The activists gained prominence when they temporarily crippled the websites of MasterCard and Paypal that cut off financial services to WikiLeaks.

A spate of cyber attacks on multinational firms and institutions, from the U.S. Central Intelligence Agency to Citigroup to the International Monetary Fund, has raised concerns that governments and the private sector may struggle to defend themselves against hackers.

In an earlier Internet posting, Anonymous said Malaysia's censorship of films and television shows and its blocking of file-sharing websites amounted to a denial of human rights.

The communication commission last week banned 10 file-sharing sites and ordered Internet service providers such as Telekom Malaysia and Maxis to block access.

The restrictions have outraged ordinary Malaysians, and several people took to Twitter on Thursday to express support for the cyber attacks.

Now to count how many sites have gotten whacked so far, said a tweet posted by Rhyden. I knew the government's IT defense team was pathetic.

The Southeast Asian country has a vibrant Internet culture that has gained a mass following in an environment where the mainstream media is tightly controlled. The government has in the past charged bloggers with sedition, often detaining suspects for long periods without trial.

(Editing by Miral Fahmy)

Cybercrime