In an apparent attempt to assuage public fears, Kim said the government will "take necessary measures based on the objective assessment" of the situation and make information available to the public.

His pledge came amid growing criticism over the government's inaction following the latest outbreak of the fatal neurodegenerative disease in the United States.

South Korea's farm ministry decided not to immediately suspend quarantine inspections, which could effectively halt all U.S. beef imports.

The apparent inaction triggered criticism that the government is not delivering on its promise that it will suspend imports in case an outbreak of mad cow disease puts public health at risk here.

The pledge was made in 2008 by key government officials, including then trade minister Kim Jong-hoon, when South Korea's decision to resume U.S. beef imports sparked fears of mad cow disease, or bovine spongiform encephalopathy (BSE).

Public fears sparked months of street rallies that spawned the strong anti-government sentiment and threatened to delegitimize the Lee Myung-bak administration that had just taken power.

While the U.S. authorities say the new case of mad cow disease poses "no risk to the food supply or to human health," two major local retailers here temporarily suspended sales of American beef, citing consumer fears.

South Korea currently imports beef from cattle below 30 months old with all specified risk materials (SRMs), known to transmit mad cow disease, removed.