The presidential office on Thursday rejected accusations the government reneged on its promise to halt American beef imports if mad cow disease breaks out in the United States, saying the situation does not merit an all-out import ban yet.

Korea has decided to continue U.S. beef imports with strengthened quarantine checks following the latest mad cow outbreak in the U.S. Opposition parties and critics urged an immediate halt to imports, claiming the government promised to do so in the event of a new mad cow outbreak.

On Thursday, a senior official at the presidential office said the government promised at the time of resuming U.S. beef imports in 2008 that it would suspend imports if public health was considered at risk after an outbreak of the disease in the U.S.

The current situation, he said, shows no sign that public health is at risk, and the latest case involving a dairy cow is not directly connected to beef that can be imported by Korea.

The official also expressed concern over misleading reports and online rumors.

The latest mad cow case reported in California is the fourth to be detected in the U.S. Seoul banned U.S. beef imports in late 2003 after the first case was reported, but fully reopened the market in 2008 after long-drawn negotiations with Washington.

Under a bilateral pact with the United States, South Korea only imports beef from animals younger than 30 months with all "specified risk materials" removed. Those materials are the parts considered capable of transmitting the variant Creutzfeldt-Jakob disease to humans. The disease is reported to have been responsible for about 150 deaths.

American beef imports have long been a politically sensitive issue in Korea.

The 2008 decision to resume imports sparked months of anti-government rallies, seriously rocking the then fledgling government of President Lee Myung-bak, amid public perceptions his government endangered public health to curry favor with the U.S.

The government stressed at the time that the decision was based on scientific grounds.

Opposition parties have stepped up their criticism of the government over its response.

"The government should carry out its promise that it would immediately halt imports if mad cow disease breaks out in U.S. beef," Park Jie-won, a senior member of the main opposition Democratic United Party, said during a party meeting.

Another DUP lawmaker Cho Kyoung-tae went a step further and urged the government to demand renegotiations of the 2008 beef import deal with the U.S. to revise the agreement in a way that strengthens hygiene conditions. (Yonhap)