By Guy Faulconbridge and Josh Smith
MOSCOW/SEOUL (Reuters) - What should the world be looking for when North Korean leader Kim Jong Un meets Kremlin chief Vladimir Putin in Russia in coming days?
The Kremlin said on Monday that Putin had invited Kim to Russia for what will be the North Korean's second known visit to Russia and his first trip abroad since the COVID pandemic.
* Who is Kim with?
If he travels with a full military delegation that could give an indication of the nature of the talks. Also of interest is who he meets besides Putin, such as Defence Minister Sergei Shoigu who visited North Korea in July.
The United States has expressed concern over what it calls advancing arms negotiations between the two countries, with White House National Security Adviser Jake Sullivan urging Kim "not to supply weapons to Russia that will end up killing Ukrainians".
The United States has accused North Korea of providing arms to Russia, but it is unclear whether any deliveries have been made. Both Russia and North Korea have denied those claims, but promised to deepen defence cooperation.
* What does Putin say?
Analysts say North Korea has huge supplies of artillery shells, rockets and small arms ammunition that could help Russia replenish the vast stocks it has expended in more than 18 months of war in Ukraine, though their quality and the country's ability to mass produce more is unclear.
Workers may also be something Russia is interested in amid record low unemployment. Before United Nations Security Council resolutions banned them in 2019, Russia was estimated to host nearly 20,000 North Koreans, according to a report by the Association of Asian Studies.
In return, Russia could offer grain, oil and military technology as Kim looks to develop capabilities such as nuclear-powered submarines and military reconnaissance satellites.
North Korea's latest Hwasong-18 intercontinental ballistic missile - its first ICBM to use solid rocket fuel - has reignited debate over possible Russian links to the nuclear-armed state's dramatic missile development.
* Anything Kim says on nuclear weapons
For the past several years, the U.N. Security Council has been divided over how to deal with North Korea. Russia and China have said more sanctions will not help and want such measures to be eased.
Whatever else comes from the meeting, the summit itself is a sign of support for each country as they face off against international sanctions and pressure.
Putin said after holding his first face-to-face talks with Kim in 2019 that proposed U.S. security guarantees would probably not be enough to persuade Pyongyang to shut its nuclear programme.
Back in 2019, Putin described Kim as "quite open" and as "thoughtful" and "interesting".
* What do Beijing and Washington say?
Communist North Korea was formed in the early days of the Cold War with the backing of the Soviet Union. North Korea later battled the South and its U.S. and United Nations allies to a stalemate in the 1950-1953 Korean War with extensive aid from China and the Soviet Union.
North Korea was heavily reliant on Soviet aid for decades, and the collapse of the Soviet Union in the 1990s contributed to a deadly famine in the North.
Pyongyang's leaders have often tried to use Beijing and Moscow to balance each other. Kim initially had a relatively cool relationship with Russia and China, which both joined the United States in imposing strict sanctions on North Korea over its nuclear tests.
* Anything quirky
Both Putin and Kim know how to catch global headlines.
Back in 2019, the two leaders attended a gala dinner where they toasted each other and watched traditional musical numbers and dancing performed by Russian artists.
The numbers included the Russian classic song "Black Eyes" and a Korean song called "the Great Commander".
The two men also exchanged gifts. Kim gave Putin a traditional Korean sword, while the Russian leader gave Kim a sabre and a tea service suitable for use on his armoured train.
Kim's rare foreign trips have occasionally offered more candid moments than what leaks from the tightly controlled state media in the North.
During his 2019 summit with U.S. President Donald Trump in the Vietnamese capital, Hanoi, Kim spoke to foreign journalists for the first time, during a photo opportunity.
That summit, for which he spent days travelling by train through China, also revealed more interactions between Kim and his sister, Kim Yo Jong. TV footage captured the North Korean leader taking a cigarette break at a railway station in the southern Chinese city of Nanning, with Yo Jong approaching him holding a crystal ashtray in two hands.
At a 2018 inter-Korean summit, 12 male bodyguards in dark suits made international headlines after they surrounded Kim’s Mercedes-Benz vehicle and jogged alongside.