Malaysia has become the latest target of cyber attacks after at least 41 government websites were hacked into overnight.
No personal or financial data were compromised in the attacks on 51 websites which saw at least 41 sites disrupted, according to industry regulator Malaysian Communications and Multimedia Commission.
The hacks come after internet group Anonymous warned it would attack the government's official portal as revenge for censoring WikiLeaks, the website that has leaked secret documents from governments and corporations.
"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.
It did not name the sites which were attacked but targets included the government's online portal malaysia.gov.my, and the webpages of the fire and emergency services department and the land public transport commission.
Malaysian police chief Ismail Omar said that although no personal or financial data had so far been stolen 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.
Anonymous had said in an earlier web posting that 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 ISPs such as Telekom Malaysia and Maxis to block access, outraging several Malaysians.
Malaysia 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.