Hackers struck Malaysian websites for a second day on Friday, an Internet regulator said, as the country scrambled to bring its government portal back online after the latest outbreak in a cyberwar waged by online activists.

The attacks followed a warning by Internet vigilante group Anonymous, which said it planned to target the Malaysian government's official portal www.malaysia.gov.my to punish it for censoring WikiLeaks.

In the attacks, which started in the early hours of Thursday, 91 Malaysian websites were hit, including 51 government webpages. Fewer attacks were reported on Friday.

The official government website was back online on Friday and most other websites had recovered, said Husin Jazri, chief executive of CyberSecurity Malaysia, which is responsible for protecting the country's cyberspace borders.

Our focus now is to halt the attack and to help the victims to get their websites up and running as usual, Husin said in a statement. The attack is still ongoing but at a reducing rate compared to yesterday.

Husin did not say how many websites were attacked on Friday.

Local media reported that Malaysian hackers also participated in the attack that was first announced this week by Anonymous, which frequently tries to shut down the websites of businesses and other organizations it opposes.

Husin said police had identified some of the hackers but gave no further details. Police officials were not immediately available to comment.

State news agency Bernama quoted Science, Technology and Innovation Minister Maximus Ongkili as saying 90 percent of the hackers were Malaysians.

Anonymous gained notoriety when it temporarily crippled the websites of MasterCard and Paypal that cut off financial services to WikiLeaks, the website that aims to hold governments and corporations to account by leaking secret documents.

Hackers have also struck multinational firms and institutions, from the U.S. Central Intelligence Agency to Citigroup to the International Monetary Fund.

Anonymous members cripple websites by overwhelming them with traffic in what are commonly known as denial of service attacks. The hacking group has also brought down websites in Syria, Tunisia, Egypt and India for political reasons.

The spate of attacks by Anonymous and other groups has raised concerns that governments and the private sector may unprepared to defend themselves.

(Reporting by Niluksi Koswanage; Editing by Alex Richardson)