North Korean leader Kim Jong Un arrived in Russia by train on Wednesday, a day before his much-anticipated summit with President Vladimir Putin that comes amid deadlocked diplomacy on his nuclear program.

South Korea's Yonhap news agency published photos of Kim, dressed in a black coat and a fedora, meeting with Russian officials at Russia's Hasan train station near its border with the North. Russian news agency Tass quoted a local official as saying Kim was given flowers, bread and salt at the station.

Kim was traveling to the Pacific port city of Vladivostok for a summit with Putin on Thursday. He became the first North Korean leader to travel to Russia since his late father, Kim Jong Il, visited in 2011.

Earlier Wednesday, the North's state media confirmed Kim's departure aboard his khaki-green armored train from an undisclosed location in North Korea. Yonhap, citing an analysis of North Korean photos on Kim's departure, speculated Kim may have left from a rural area, not Pyongyang.

Kim was expected to arrive in Vladivostok around late Wednesday afternoon and attend a dinner reception hosted by Russian Deputy Prime Minister Yury Trutnev, according to South Korean media. After his summit with Putin, Kim may tour neighboring facilities or landmarks before departing for home on Friday, the reports said.

Kremlin adviser Yuri Ushakov told Russian media the summit will focus on North Korea's nuclear program, noting that Russia will seek to 'consolidate the positive trends' stemming from President Donald Trump's meetings with Kim.

In February, Kim's second summit with Trump in Hanoi ended without any agreement because of disputes over US-led sanctions. There have since been no publicly known high-level contacts between the US and North Korea, though both sides say they are still open to a third summit.

Kim wants the US to ease the sanctions to reciprocate some partial disarmament steps he took last year. But the US maintains the sanctions will stay in place until North Korea takes more significant denuclearization steps.

Some experts say Kim could try to bolster his country's ties with Russia and China. Others say it's not clear how big of a role Russia can play in efforts to restart the nuclear negotiations. The summit could allow Putin to try to increase his influence in regional politics and the standoff over North Korea's nuclear program.

'Kim wants to show that he's cooperating with Russia too, rather than looking to only the US and China. But I think it's not easy for Russia and China to provide North Korea with practical assistance that leads to the inflow of dollars,' said Chon Hyun-joon, a former senior researcher at the Korea Institute for National Unification in Seoul.

North Korea has increasingly expressed frustration at the deadlocked negotiations. Last week, North Korea tested a new weapon and demanded US Secretary of State Mike Pompeo to be removed from nuclear talks.

Putin's adviser added that the Kremlin would try to help 'create preconditions and a favorable atmosphere for reaching solid agreements on the problem of the Korean Peninsula,' Ushakov said.

Ushakov pointed at a Russia-China roadmap that offered a step-by-step approach to solving the nuclear standoff and called for sanctions relief and security guarantees to Pyongyang. He noted that the North's moratorium on nuclear tests and scaling down of US-South Korean military drills helped reduce tensions and created conditions for further progress.

Ushakov said that Putin-Kim summit's agenda will also include bilateral cooperation. He added that Russia's trade with North Korea is minuscule at just $34 million last year, mostly because of the international sanctions against Pyongyang.

Russia would like to gain broader access to North Korea's mineral resources, including rare metals. Pyongyang, for its part, covets Russia's electricity supplies and investment to modernize its dilapidated Soviet-built industrial plants, railways and other infrastructure.

In the meantime, Vladivostok has been seeing a number of unusually strict security measures. Maritime authorities said that the waters around Russky Island, off the southern tip of Vladivostok, would be temporarily closed to all maritime traffic.

The island has a university with a conference hall and is seen as a likely summit venue.

Separately, local media reported that some platforms at Vladivostok's main train station would be closed for several days, and that buses will be rerouted from the train station Wednesday. News website Vl.ru reported on road construction to even out the entrance at the train station, possibly to allow Kim's limousine to drive straight off the platform.