North Korea and Japan have begun unofficial negotiations for the possible repatriation back to Japan of Red Army members who hijacked a Japan Air Lines jetliner more than 30 years ago.

An official from the Japanese Foreign Ministry said the negotiations are being held on the premise that North Korea would unconditionally return the four surviving hijackers to Japan.

Nine members of the Red Army hijacked the Yodo passenger jet in 1970, during a domestic flight from Tokyo, diverting the flight to Seoul before eventually landing in Pyongyang.

The hijackers were granted political asylum in North Korea. Since then, three of the nine have died and two others have returned to Japan, where they were convicted for their roles in the hijacking.

The remaining four recently sent a letter to the North Korean government expressing their wish to return to Japan.

The North's official Korean Central News Agency said earlier this week that North Korea will not oppose their return to Japan.