By Jack Kim
SEOUL (Reuters) -North Korean leader Kim Jong Un is expected to visit Russia's far-eastern port city of Vladivostok by armoured train this month to meet President Vladimir Putin, possibly to discuss supplying Russia with weapons for its war with Ukraine.
The trip, which has not been officially confirmed, would be his first visit abroad in more than four years and the first since the coronavirus pandemic.
It is likely to take almost a full day to travel more than 1,000 km (600 miles) to Vladivostok across the border with Russia, taking account of the North's sometimes archaic rail network.
While he has made more trips abroad than his father, Kim Jong Il, as leader, Kim's travel is often shrouded in secrecy and heavy security. Unlike his father who was said to be averse to flying, Kim has flown his personal Russian-made jet for some of his trips.
In 2004, there was a huge explosion at a rail station near the Chinese border after Kim Jong Il passed on train returning from China, killing more than 100 people. The cause, and whether it was an assassination attempt, were never confirmed.
The following are Kim Jong Un's foreign visits since taking power in 2011.
* March 25-28, 2018: Making his first foreign trip as leader, Kim visits China, the North's main political ally and economic benefactor. He travels to Beijing by a special train and holds a summit with Chinese President Xi Jinping.
The train, with its signature green paint, is believed to include more than 20 armoured cars and equipped with a communications system and a special cabin for Kim with a bright white interior where he has been seen at work and holding meetings with aides, according to North Korea's official media and South Korean analysts.
* April 27, 2018: Kim steps across the inter-Korea border in the Panmunjom truce village for a summit with South Korean President Moon Jae-in. It is the first time a North Korean leader has set foot in the South, Kim's first summit with a South Korean leader and the third ever by a North Korean leader. The two pledge to improve ties, end military confrontation and bring peace and common prosperity.
* May 7-8, 2018: Kim flies his personal Ilyushin jet to the northeastern Chinese city of Dalian and holds a summit with Xi. The two discuss deepening ties between the traditional allies. The visit comes amid expectations of Kim's summit with U.S. President Donald Trump.
* June 10-12, 2018: Kim takes an American-made Boeing 747 operated by Air China on a direct flight from Pyongyang to Singapore for the first summit between North Korea and the United States. The meeting results in a joint statement on establishing new relations between the two countries, giving security guarantee for North Korea and a pledge by the North to end its nuclear programme.
* June 19-20, 2018: Kim visits China on his Ilyushin jet and discusses the denuclearisation of North Korea with Xi in Beijing. Accompanied by senior economic aides, Kim tours Chinese industrial facilities and an agricultural research centre.
* Jan 7-10, 2019: Kim visits China for a fourth time, travelling to Beijing by train amid expectations of a second summit with Trump.
* Feb. 26-28, 2019: Kim visits the Vietnamese capital of Hanoi for a second summit with Trump. He takes the train from Pyongyang through China over three days to Vietnam. After two days of meetings, the talks between Kim and Trump collapse over disagreement on lifting sanctions imposed on the North and how to dismantle its nuclear programme.
* April 24, 2019: Kim visits Vladivostok for his first summit with Putin. Kim takes the train for the nearly day-long trip, crossing the Tumen River border into Russia.
* June 30, 2019: Kim steps across the inter-Korean border for talks with Trump.
* September 2023: Kim is expected to visit Vladivostok, again by train, for a summit with Putin, which would be his first trip abroad in more than four years.
(Reporting by Jack Kim; Editing by Nick Macfie)