South Korea and the United States have agreed to cooperate in fighting cyber attacks against their defence networks from countries including China and North Korea, officials said Monday.

The April 30 deal calls for an exchange of information on detecting and fighting cyber attacks against information systems used by the militaries of the two allies, the defence ministry said.

At least once a year the two countries will hold a conference on joint readiness against hacking, it said.

"The deal covers cyber attacks in general, including those from and China," a ministry official told AFP on condition of anonymity.

Last year Prime Minister Han Seung-Soo warned his cabinet against what he called attempts by Chinese and North Korean computer hackers to obtain state secrets.

In 2004 hackers based in China used information-stealing viruses to break into the computer systems of Seoul government agencies.

Im Jong-In, a cyber expert at Korea University, said South Korea -- one of the world's most wired societies -- needed an integrated unit to fight by North Korea.

He told Monday's Munhwa Ilbo newspaper that the North appeared to have hacked South Korean government computer systems through servers in .

(c) 2009 AFP