Seoul, July 9 (IANS): A flight tracking website on Monday detected North Korean leader Kim Jong-un's private jet in the Russian city of Vladivostok leading to speculations that the preparations for his visit might be underway.

Flightradar24 detected the jet, called Chammae-1, landing in Vladivostok on Monday and taking off for Pyongyang just about three hours later, Efe news reported.

Despite the usual opacity of the North Korean regime, which keeps many of its leader's movements a secret, the short stay of the Chammae-1 on Russian territory suggested that it was a visit by the advance team in the face of Kim's possible visit to the city in September, the report said.

Russian President Vladimir Putin invited Kim to attend the Eastern Economic Forum in September in the Russian coastal city, although Pyongyang has not yet responded to the invitation.

South Korean President Moon Jae-in, Chinese President Xi Jinping and Japanese Prime Minister Shinzo Abe have also been invited to this year's forum.

If Kim and the rest attend the forum, it would be an exceptional event, in which leaders of five of the six nations that have been working since the last decade to achieve the denuclearization of the Korean peninsula would meet.