Intelligence officials will be questioning a group of nine North Korean defectors sent by Japan to Seoul and who say they want to stay in South Korea.

One of the nine is believed to be a grandson of a senior North Korean judge.

A Japanese coast guard vessel found the North Koreans -- three men, three women and three children -- drifting aboard a small wooden boat off Japan's west coast Sept. 13, ending a six-day journey by sea from North Korea to Japan.

They were questioned by Japanese officials before being sent to South Korea aboard a Korean Air flight this week, a report by Yonhap news agency said.

"All of the North Koreans expressed their wish to defect to South Korea and the government accepted them from a humanitarian perspective with respect to their free will," Seoul's Foreign Ministry spokesman Cho Byung-jae said.

Cho gave no other details, including the defectors' identities, citing concerns for their safety.

It is the first time in about four years that defectors from North Korea arrived in the South after reaching Japan by sea.

They arrived at Incheon Airport wearing hooded jackets, white face masks and sunglasses and immediately were driven away in several vans to an undisclosed destination.

Yonhap reported a South Korean diplomatic source saying one of the defectors claimed to be a grandson of Paek Nam Un. Paek, a former chairman of the North Korea's Supreme People's Assembly, died in 1979.

The defector's identity "is a matter that needs to be confirmed in an interrogation," the source said.

The defectors, who are from two families, left Oudaejin in northern North Korea Sept. 8, a report by the Japanese newspaper Yomiuri Shimbun said.

They were rescued around 10 miles out to sea from the Japanese city of Wajima, Ishikawa Prefecture.

Japanese officials said they changed their plan from landing in South Korea because of severe storms.

Japanese government sources said one man told officials that he organized the defection. Another man reportedly said he had run a black-market business in North Korea but left for the sake of his children's future.

The last North Koreans to defect to Japan by sea arrived in June 2007 when Japanese coast guard boats found a family of four aboard a small boat off Fukaura-machi, Aomori Prefecture.

In 1987, 11 North Koreans drifted into a central Japanese port and later defected to South Korea in the first defection via Japan.