The United Nations and United States on Friday took Laos and China to task for forcing nine young asylum seekers back to North Korea, warning that the countries were flouting international commitments.
"We are extremely concerned for the protection of this group, which includes up to five minors, who are at risk of severe punishment and ill treatment," said Rupert Colville, spokesman for the UN high commissioner for human rights.
"We are dismayed that the governments of Laos and China appear to have abrogated their non-refoulement obligations, especially given the vulnerability of this group, all of whom are reported to be orphans," Colville told reporters in Geneva.
"Refoulement" is the term used under international law for unjustly sending a refugee home.
In Washington, State Department spokeswoman Jen Psaki said the United States was "very concerned" by the forced repatriation.
"We urge all countries in the region to cooperate in the protection of North Korean refugees within their territories," she told reporters.
"We do remain very concerned about their well-being, and we're monitoring it closely," she said.
The nine, arrested in Laos some three weeks ago, were returned to neighbouring China on Monday and flown back to North Korea the following day.
North Korean defectors traditionally try to make the journey to South Korea by first heading to China and then proceeding onwards from other countries.
Laos previously had been seen as a relatively safe transit point.
"We urge the Chinese and Laotian authorities to publicly clarify the fate of the nine young North Koreans, as well as the conditions under which they were returned," Colville said.
He also urged North Korea to allow independent monitors immediate access to the group.
North Korean leader Kim Jong-Un is believed to have tightened border controls since he came to power after the death of his father Kim Jong-Il in December 2011.
The number of refugees arriving in South Korea plunged more than 40 percent to 1,508 last year.
"The situation of returnees to North Korea has been a constant source of concern for many years. They can receive very severe punishment merely because they have left the country," Colville said.
"Before anyone is sent back, we need to assess their asylum claim, and ensure they will be secure if they are sent back. That's a process that should be gone through, rather than some summary return," he said.
Dan McNorton, spokesman for the UN high commissioner for refugees, said his agency was "gravely concerned" for the group's safety.
"All countries should refrain from any measures, directly or indirectly, that lead to the return of a person to a country where his or her life will be threatened," he told reporters.