NorthKoreaStudentsParade
Students carrying party flags stand under statues of former North Korean leaders Kim Il Sung and Kim Jong Il at the beginning of a mass rally and parade in the capital's main ceremonial square, a day after the ruling party wrapped up its first congress in 36 years, in Pyongyang, May 10, 2016. REUTERS/Damir Sagolj

Several more North Korean workers have fled their jobs in an overseas restaurant run by the isolated North, South Korea's Unification Ministry said on Tuesday after a media report said three people had escaped from China and were claiming asylum.

New Focus, a Seoul-based website run by North Korean defectors with sources in the North, said three workers from an unidentified restaurant in Shanghai had fled to a third country, citing an unidentified source.

South Korea's Munhwa Ilbo newspaper reported earlier on Tuesday that the workers were in Thailand. It also cited an unidentified source.

The latest reports follow the defection of 13 North Korean workers from a restaurant run by the secretive North in China in April, a case South Korea described as unprecedented.

North Korea has accused South Korea of a "hideous abduction" and released interviews on state media with the families of some of the workers who arrived in the South in the April incident.

In the latest case, South Korea's Unification Ministry confirmed that some North Koreans working in a restaurant overseas had recently "broken away".

An official said the ministry could not confirm whether they had entered South Korea, how many workers had defected, and where they currently were.

The two Koreas have remained in a technical state of war since their 1950-53 conflict ended in a truce, not a peace treaty. In recent years they have been locked in a prolonged period of rhetoric and heightened tension.

North Korea has adopted a different strategy on defectors under leader Kim Jong Un, displaying those who later defect back to the North on state television and bringing the families of others to Panmunjom on the border between the two states.

Seven of other restaurant workers who did not join the 13 in defecting in April returned to Pyongyang and were later shown to a CNN reporter on a trip to North Korea.

The families of some of the defectors were also interviewed by CNN in May.