Despite a flurry of promising steps in the effort to get North Korea to abandon nuclear weapons this week, Secretary of State Condoleezza Rice found herself next door on Saturday defending the dignity of American cattle.

In South Korea, the country most immediately threatened by its only immediate neighbor, the long-running drama over North Korea's atomic activity has been eclipsed by a bitter dispute over U.S. beef imports that has threatened the government of President Lee Myung-bak.

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Thus, a day after Pyongyang demolished the most visible symbol of its nuclear programs, beef trumped bombs as Rice faced a barrage of questions about the safety of American steaks, chops and burgers after telling reporters she hoped the issue wouldn't distract from other matters.

"I want to assure everyone that American beef is safe," she told a news conference with South Korean Foreign Minister Yu Myung-hwan. "We will continue to work with you to have consumer confidence in that matter. We want there to be consumer confidence in American beef."

But Yu said the issue was unlikely to fade quickly.

"It will take time for that risk to be erased from the minds of the Korean public," he said.

For many South Koreans, who have lived with threats from their communist neighbor for five decades, the nuclear issue is of less concern than Seoul's agreement to lift a ban on American beef imports in April as a way to restore strained ties with Washington.

Activists have been staging daily rallies on the streets of the capital to voice fears about possible health risks such as mad cow disease. As officials began inspecting U.S. beef on Friday before it can reach markets, hundreds of labor activists blocked customs storage facilities.

A small but loud and angry group of about 15 sign-carrying protesters gathered outside the South Korean Foreign Ministry where Rice was meeting with Yu.

"Rice go home," they chanted, waving placards, some of which read "Stop Rice and Mad Cow," and "We Don't Need U.S. Troops. We Don't Need Mad Cows."

A squad of black-clad police surrounded the demonstration, although it was tiny compared to earlier rallies that drew 80,000 people at their peak but have since dwindled. On Thursday, about 3,000 protesters clashed in central Seoul with riot police, who used water cannons and fire extinguishers to repel crowds.

U.S. beef had been banned from South Korea for most of the past 4 1/2 years, since the first case of mad cow disease in the U.S. was discovered in late 2003. In the wake of public outrage over plans to resume shipments of American beef, the entire South Korean Cabinet has offered to resign and the president has reshuffled his top advisers.

Seoul agreed to resume U.S. beef imports only after American producers agreed to limit shipments to meat from cattle younger than 30 months, believed less susceptible to mad cow disease. The restriction has been deemed a transitional step that will be lifted when conditions change in the South.

En route to Seoul from meetings in Japan where North Korea dominated the agenda, Rice expressed hope that South Koreans would accept official assurances there are no health issues with American beef.

"We hope that in time the South Korean people will listen to that and will be willing to listen to what their government is saying and what we're saying," she told reporters aboard her plane said en route to Seoul. "The U.S. believes strongly in the safety of its product."

Rice did manage to briefly address the North Korea developments, saying that Friday's destruction of the cooling tower at its main nuclear facility was significant but stressing that far more had to be done.

The demolition followed moves earlier this week by the U.S. to lift sanctions against Pyongyang, in response to North Korea's submission of a long-delayed declaration of its nuclear programs.

"I expect that the North will live up to the obligations that it's undertaken, to take those concerns seriously and to address them," Rice said of suspicions left out of the declaration, such as Pyongyang's alleged uranium enrichment and nuclear proliferation.

"At the end of this, we have to have the abandonment of all programs, weapons and materials," she said.

After seeing Yu, Rice met with President Lee and briefed him on recent progress in the nuclear standoff. Lee told her that the two countries should work closely to get Pyongyang to give up all nuclear weapons and programs, a statement from the presidential Blue House said.