SEOUL — South Korean activists for human rights in North Korea are intensifying their campaign against China’s harsh treatment of North Korean refugees, demanding asylum for a defector who faces execution if China sends him back to North Korea.

The efforts on behalf of 33-year-old Lee Sang Hyuk, arrested in the Chinese city of Yanji about 30 miles from the Tumen River border with North Korea, coincide with mounting pressure here and in America to get China to abandon its policy of returning all refugees to North Korea as “economic migrants.” Advocates hope that instead, the refugees will be accepted as escapees from a repressive regime. Refugees have for years been saying that China’s policy of sending them back to North Korea means torture and probable death, either by beating under interrogation or by a formal sentence carried out by a military firing squad.

The most prominent North Korean defector, Hwang Jang Yop, once the chief secretary of the ruling Workers’ Party of North Korea, issued an “emergency statement” on behalf of the Committee for Democratization of North Korea after the arrest of Mr. Lee and one other defector by China’s border police was disclosed one week ago. Mr. Lee was believed to have been tracked down after North Korean police gave their colleagues in China a list of Mr. Lee’s telephone contacts that they had found in one of his notebooks.

“Mr. Lee would die at once if he is sent to North Korea,” said the statement, sent to South Korean authorities as well as Secretary-General Ban Ki-moon of the United Nations, who was South Korea’s foreign minister before assuming his U.N. post in January. “It is urgent that we stop his repatriation.”

The statement was not expected, however, to excite the attention of South Korea’s government, immersed in promoting ties with North Korea in the wake of the summit in Pyongyang early October between South Korea’s president, Roh Moo-hyun, and North Korea’s leader, Kim Jong Il.

Mr. Roh has warned against offending North Korea by calling for “reform” and “openness” of the North and did not raise the issue of “human rights,” a term that North Korean officials view as deeply insulting. Mr. Roh inquired about the fates of nearly 500 South Koreans, mostly fishermen, held in North Korea as well as South Korean soldiers held as prisoners ever since the Korean War, but Mr. Kim reportedly brushed off the inquiry as premature. Members of Mr. Roh’s entourage said North Koreans told them all the South Koreans in North Korea had chosen “voluntarily” to stay on.

Advocates for North Korean refugees, however, hoped that the American government, prodded by congressional hearings reflecting conservative skepticism about North Korea’s pledge to get rid of its nuclear weapons program, would support their plea for China to free Mr. Lee and his colleague, identified only as “Kim,” a common Korean surname.

“We solemnly demand the government of China allow political asylum to Mr. Lee and his colleague currently in China’s custody,” said the statement by Mr. Hwang’s democratization committee. “As political asylees, they are entitled to protection accorded them under the international human rights conventions.”

Strategists behind the campaign for Mr. Lee, his colleague — and as many as 300,000 North Koreans believed to be hiding out in China — say they hope China’s need to burnish its international image before next year’s Olympic games in Beijing would encourage Chinese authorities to adopt a lenient attitude. They had counted on sympathy and support from evangelical Christians in America, as evidenced at a meeting on October 11 and 12 in Arlington, Va., of conservative American Christians and U.N. officials, including Secretary-General Ban.

The Rev. Suh Seung Won, international director of Saving North Korea, asked American religious groups at the meeting to publicize the hardships of North Koreans and called on the American government to accept North Koreans as refugees. So far America has agreed to accept only a handful of North Korean refugees and is currently scrutinizing the records of 30 refugees held in a camp in Thailand. North Korean refugees have fled in recent years through China to Thailand, Vietnam, Hong Kong, Mongolia, and Russia but prefer to get to Thailand through Laos with the help of guides paid by refugee groups or friends and relatives. Thai authorities have a policy of holding them until they find safe haven, usually in South Korea, to which about 10,000 have made their way in the past decade. Mr. Ban told the evangelicals that the U.N. “wants to continuously work together with religious organizations for human rights issues,” but church members here have criticized him for his reluctance to bring real pressure on North Korea to improve its record.

Privately, evangelical Christians were critical of a report by Vitit Muntarbhorn, a U.N. “special rapporteur” on human rights in North Korea, who reported “constructive developments” in North Korea’s record on human rights though North Korea refused to grant him a visa.
In his report, Mr. Muntarbhorn noted that North Korea was a signatory to four human rights treaties and credited North Korea with “collaborating quite well with U.N. agencies” by providing access after severe flooding in August. At the same time, he called on North Korea to “reform its prison system, eliminate violence against the human person, address effectively the issue of abductions/disappearances and promote due process of law and the rule of law.”

Daily NK, an Internet news organization here that reports on North Korean human rights issues, said Mr. Lee had been jailed in North Korea for using a cell phone to call relatives in South Korea but had managed to escape across the Tumen River border into China after North Korean authorities had seized his cell phone and phone list. Chinese authorities were alerted after he made calls to some of the numbers from a phone in Yanji.

“He will hardly survive,” a defector here was quoted as telling Daily NK, predicting that China’s public security agency would turn both Mr. Lee and Mr. Kim over to North Korea’s national security agency “in compliance with strong demands” from the North.

Although South Koreans are often indifferent to the plight of North Koreans, stories of abuses in the North have been increasingly widespread here since Mr. Hwang defected to the South Korean Embassy in Beijing 10 years ago. The co-leader of Mr. Hwang’s democratization committee is Kang Chol Hwan, author of the book “Aquariums of Pyongyang,” who was received by President Bush at the White House in June 2005.

Another North Korean refugee, Shin Dong Hyuk, has recently published a memoir in which he writes that his mother was hanged and his older brother shot dead before his eyes after they tried to escape. Mr. Shin, who was 14 at the time, berated South Koreans for looking on “horrific stories” from North Korea as “old news” and criticized President Roh for having praised North Korea during his recent visit to Pyongyang.

A Korean-American businessman, Steve Kim, freed recently after four years in prison in China for helping North Korean refugees, said he had seen guards beating North Korean defectors “to a pulp.”

He suggested in an interview with Chosun Ilbo, a leading newspaper here, that China’s attitude toward North Korean refugees might inflame international public opinion in the run-up to next year’s Olympics.

“The slogan of the Beijing Olympics is ‘One World,'” he was quoted as saying, “but the reality is that North Korean defectors are being persecuted all the more seriously.” He said he was “concerned that there could be a massive roundup of North Korean refugees before the Olympics.”