SEOUL: South Korea announced it would set up a military command next year to tackle the threat of cyber warfare from North Korea, amid suspicions the North was behind virus attacks earlier this week.

The information security command will be launched on January 1, two years earlier than planned, and become operational in July, said Kim Jae-Min, a defence ministry official in charge of the project.

The National Intelligence Service (NIS) warned of a possible third wave of cyber assaults, after identifying the communist North as a suspect in earlier attacks that temporarily crippled South Korean and US websites.

The White House, State Department and Pentagon websites were among those targeted in the initial attack, US experts said separately.

The hacking programme hit 12 South Korean and 14 US organisations early this week.

The NIS said in a statement a second wave of attacks on Wednesday was aimed at domestic banks and a security solution provider, and it fears a third round which may target infrastructure such as energy and telecommunications.

The spy agency, which was itself reportedly targeted, said it has urgently distributed "vaccine" programmes to 10 security solution providers.

Its public statement did not suggest the source of the "distributed denial of service" (DDoS) viruses, which invade thousands of personal computers and are programmed to swamp selected websites.

But Park Jie-Won, a member of parliament's intelligence committee, said the NIS told members on Wednesday it believed the North or its sympathisers was to blame.

"The NIS claimed the attack was presumed to have been staged by North Korea or followers, without presenting evidence," Park, from the opposition party, told AFP.

The communist state has staged a nuclear test and numerous missile launches in recent weeks, raising regional tensions. A cyber attack, if confirmed, would be a new tactic.

Yonhap news agency quoted a NIS report to the committee as forecasting potential "financial chaos" in the event of a larger cyber attack.

It said the daily value of all online transactions in South Korea - one of the world's most wired nations - is six trillion won (4.7 billion dollars).

The NIS said the internal networks of the Seoul government are safe and no information has been leaked.

The government's Korea Information Security Agency said most sites had been restored after the first attacks began in the country late Tuesday - using 12,000 domestic PCs and 8,000 abroad.

However it said a second round - using 29,000 hijacked PCs - was hitting one foreign site and 15 domestic sites, including government agencies and banks and a security solution provider.

Yonhap said victims included the US-South Korea Combined Forces Command, whose server is based in the United States, the National Intelligence Service and South Korea's top security solution provider AhnLab.

AhnLab predicted a third DDoS attack would start at 6:00 pm (0900 GMT) against seven domestic sites.

"This is the worst cyber attack I have seen in my 15-year career," its CEO Hongsun Kim told reporters. "This is an online equivalent of 9/11.

"I don't think an individual hacker can do this. This is an organised attack," he said, adding "very complicated" codes are being planted.

In Washington the Department of Homeland Security confirmed US government and private websites came under attack but declined to identify them.

"It was a pretty massive attack," Johannes Ullrich, chief technology officer for the private US SANS Internet Storm Centre, said of the assault which began in the United States last weekend.

He said government sites which were hit included the White House, Department of Homeland Security, Department of Transportation, Federal Aviation Administration, National Security Agency, State Department, US Postal Service, US Treasury Department and Voice of America.

A Pentagon site was also targeted, he said. - AFP/de