North Korea says its ambassador to Cuba has paid a farewell visit to Cuban President Miguel Diaz-Canel before concluding his mission. South Korean media say the decision to replace him may be linked to the establishment of diplomatic relations between Cuba and South Korea.

North Korea's ruling Workers' Party newspaper, Rodong Sinmun, reported on Monday that Ma Chol Su met the Cuban president on Saturday.

The paper quoted Diaz-Canel as saying that Cuba will stand against the two countries' common adversary, the United States, and continuously advance their traditional socialist ties between Havana and Pyongyang.

Cuba has an embassy in North Korea, but established diplomatic ties with South Korea last month.

South Korea's Unification Ministry said the move must have dealt a considerable blow to the North.

The Tokyo-based Radiopress news agency says it is probably the first time that North Korean media have mentioned Cuba since the Caribbean country formed official relations with Seoul.

South Korea's Yonhap News Agency reported that the ambassador's replacement "came at a delicate moment" and is causing speculation that the diplomatic event "might have influenced the change of the ambassador."