Twenty-nine people, believed to be North Koreans, are in the Japanese Embassy in Beijing. Earlier, the group broke into the compound of a Japanese school in the Chinese capital. The incident is likely to spark a sensitive round of diplomacy involving several Asian nations.
The 11 men, 15 women, and three children are said to be asking for asylum in a third country. Video footage broadcast in Japan showed a stepladder, folding chairs, wire cutters, and a woman's sandal near holes cut through two fences surrounding the Japanese school in Beijing.
Japanese officials say the asylum seekers briefly scuffled with guards outside the school.
Japanese Foreign Ministry spokesman Akira Chiba says the group was quickly taken by car from the school to an embassy office.
"Now we are trying to find out where they came from," said Akira Chiba. "At this moment we are not sure if they are from North Korea, but apparently they are speaking in the Korean language."
Mr. Chiba says there was no confrontation with Chinese authorities.
For the past three years, dozens of North Korean refugees have sought asylum at foreign diplomatic facilities and schools in China. Most have been taken to a third country before going on to South Korea.
But if the Chinese authorities catch them, the refugees are sent back to North Korea.
Tens of thousands of North Koreans fleeing starvation and repression at home have crossed into China. Many hope to eventually reach South Korea.
Meanwhile, Vietnam denied it was involved in last month's airlift of more than was 460 North Korean refugees. A Foreign Ministry spokesman in Hanoi says reports about Vietnam's role are groundless.
Diplomats and human-rights workers say the refugees flew to South Korea from Vietnam, but Seoul has not confirmed that.
North Korea reportedly withdrew its ambassador from Vietnam to express its anger over the airlift. Pyongyang has criticized its fellow communist state by accusing it of conspiring with South Korea and the United States in the incident.
Pyongyang lashed out after the airlift, saying the refugees had been kidnapped by the South.