Three teenage North Korean defectors who were arrested in Laos have been freed and handed over to the South Korean embassy, officials say.
Protests were held outside the Laos embassy in Seoul over the case
They had spent five months in custody while their case was investigated.
Activists say the three could become the first refugees to go to South Korea from Laos, normally reluctant to offend its communist allies in Pyongyang.
Meanwhile, 400 North Korean refugees in Thailand are reportedly on hunger strike over resettlement delays.
Human rights groups said the refugees, 314 of whom are women, are angry at delays by the South Korean government in giving them permanent refuge.
Their living conditions at the detention centre in Bangkok were harsh, Lee Ho-taeg of the International Campaign to Block the Repatriation of North Korean Refugees said.
"About 300 women are held in the facility, which is barely enough for 100 people. There is only one toilet and more than 300 women have to share it," he told the AFP news agency.
Thai immigration police denied there was trouble.
"Nothing's happening," Lieutenant Colonel Prawit Sirithorn said. "Some of them might have been stressed out because of the heat."
South Korean Foreign Minister Song Min-soon said only that Seoul was working with Bangkok to "resolve the issue smoothly".
The three teenagers in Laos, aged 12, 13, and 17, are reported to have entered China in 2002, eventually making their way to Laos.
Their detention in Laos made headlines after they wrote a letter to a Japanese rights group appealing for help.
"We have come this far in search of freedom. We are unfortunate children who may die just because we wanted freedom," the 13-year-old, identified as Choi Hyang, wrote.
The Laos government confirmed it had handed over the teenagers to the South Korean mission, but insisted they were South Koreans who had been trafficked into the country.
"After investigations which took some time, the Lao government decided that although they entered illegally, they couldn't go on trial because they were underage," foreign ministry spokesman, Yong Chanhthalansy, told Reuters news agency.
Increasing numbers of North Koreans are believed to be fleeing their impoverished country into China, often making their way to other Asian countries such as Thailand or Mongolia to seek asylum.
While many are helped by South Korean rights organisations, the journey is hazardous.
China, an ally of the North, has an agreement to repatriate them as economic migrants. Rights groups say the North has toughened punishments for would-be defectors, with longer prison terms, beatings and starvation.
South Korean diplomats have been accused by rights groups in the past of failing to help them for fear of provoking Pyongyang.