Hanoi  - The Vietnam Computer Emergency Response Team (VNCERT) has received an "official complaint" from its South Korean counterpart, the Korea Internet Security Center (KrCERT), about a Vietnamese cyber-security firm's efforts to track down the source of computer virus attacks on websites in South Korea and the US, officials said Tuesday.

The virus attacks earlier this month on sensitive government and business websites in the US and South Korea caused widespread concern. The source of the attacks was variously reported to be North Korea, Britain and elsewhere.

"I am very frustrated with this case because I had not expected the way people would respond to our help," said Nguyen Tu Quang, director of leading Vietnamese cyber security company Bach Khoa Internetwork Security (BKIS).

Shortly after the cyber-attacks were made public in early July the BKIS centre claimed to have traced the source of the attacks to a master server in Britain.

Vietnamese media for the past few days quoted officials from VNCERT, the state-agency authorized to handle incidents that originate in Vietnam networks as well as reported by any foreign persons or institutions, as saying BKIS had breached Vietnamese and international rules during its investigation of the cyber-attacks.

VNCERT said it had received an "official complaint" on July 16 from its Korean counterpart KrCERT, stating the South Korean agency had never requested BKIS to help investigate the attacks, as BKIS had claimed.

"It is a very sensitive case," said Quang. "BKIS is only a small centre, but successful in finding the origin of attackers, and then we get in trouble." (dpa)