SEOUL, South Korea - South Korean police said Monday they would request help from China to track the origins of cyber attacks that briefly crippled US and South Korean government and commercial websites in July.

"We are now seeking help from Chinese authorities to launch a joint investigation," a national police agency official told AFP, speaking on condition of anonymity.

The move follows last week's remarks by South Korea's intelligence service chief Won Sei-Hoon blaming North Korea's telecommunications ministry for the attacks.

"Our search into the route of the attacks on South Korean and US sites found a line coming from China," Won told a parliamentary session last Thursday, Yonhap news agency and local newspapers reported at the time.

"The line was found to be on the IP (Internet protocol) that the North Korean Ministry of Post and Telecommunications is using on rent (from China)," Won said.

It was the first time the South's National Intelligence Service had named a specific body as the user of the IP address linked to the attacks.

The intelligence agency had said in July that North Korea was a prime suspect in the "distributed denial of service" attacks designed to swamp selected websites with traffic.

The attackers infected tens of thousands of "zombie" computers with a virus which programmed them to send a flood of requests for website access.

But the origin of the attacks was never confirmed, with one Vietnamese expert saying they originated from a master server in Britain. Experts say North Korea maintains elite hacker units.

The threat of cyber warfare by its neighbour has prompted South Korea to establish a specific military command, which will be active by next year. Last week Lieutenant General Jeffrey Remington, commander of the US Air Force in South Korea, called on Washington and Seoul to take "aggressive steps" to safeguard their military computer networks from increasingly sophisticated cyber attacks.