Putin showed Kim around Russia's most advanced space rocket launch site in Russia's Far East and discussed the possibility of sending a North Korean cosmonaut into space. Kim, who arrived by train from North Korea, asked detailed questions about rockets as Putin showed him around the Vostochny Cosmodrome.
After the tour, Putin, 70, and Kim, 39, held talks for several hours with their ministers and then discussed world affairs and possible areas of cooperation one-on-one, followed by an opulent lunch of Russian "pelmeni" dumplings stuffed with Kamchatka crab and then sturgeon with mushrooms and potatoes.
Kim raised a toast with a glass of Russian wine to Putin's health, to the victory of "great Russia" and to Korean-Russian friendship, predicting victory for Moscow in its "sacred fight" with the West in the Ukraine war.
"The Russian army and people will certainly win a great victory in the sacred struggle for the punishment of a great evil that claims hegemony and feeds an expansionist illusion," Kim said, raising his glass.
US and South Korean officials have expressed concern that Kim could provide weapons and ammunition to Russia, which has expended vast stocks in more than 18 months of war in Ukraine. Moscow and Pyongyang have denied such intentions.
Putin gave numerous hints that military cooperation was discussed but disclosed few details. Defence Minister Sergei Shoigu attended the talks. The Kremlin said sensitive discussions between neighbours were a private matter.
When asked by Russian media if Moscow would help Kim build satellites, Putin said: "That's why we came here."
Washington warned it would implement further sanctions over any weapons transfers by either country to the other, and said Putin was "begging" Kim for help after losing tens of thousands of troops in Ukraine.
"We have taken a number of actions already to sanction entities that brokered arms sales between North Korea and Russia, and we won't hesitate to impose additional sanctions if appropriate," US State Department spokesman Matthew Miller said at a briefing.
He called it "troubling" that Russia would discuss cooperation with North Korea on programs that potentially would violate UN Security Council resolutions.
UN Secretary-General Antonio Guterres signalled Moscow had to tread carefully.
"Any form of cooperation of any country with North Korea must respect the sanctions regime that was imposed by the Security Council," Guterres told reporters, adding that it was "extremely relevant" in the case of Russia and North Korea.
For Russia, the summit was an opportunity to needle the United States, the big power supporter of Ukraine, though it was unclear just how far Putin was prepared to go in fulfilling any North Korean wish lists for technology.
Putin said Kim now planned to visit military and civilian aviation factories in the Russian city of Komsomolsk-on-Amur and to inspect Russia's Pacific fleet in Vladivostok.
Russian Foreign Minister Sergei Lavrov will visit Pyongyang for more talks next month, the Kremlin said.
Putin accepted an invition from Kim to visit North Korea in the future, the North's state news agency KCNA reported.
'COMRADES'
Putin and Kim called each other "comrades" at lunch and Putin repeatedly reminded Kim that it was the Soviet Union that backed North Korea - and was first to recognise it just over 75 years to the day since it was established.
Amid the Ukraine war, which has become a grinding artillery war of attrition, the United States and Kyiv's other allies are watching to see if Kim's visit paves the way for a supply of artillery shells to Russia.
Britain urged North Korea to end arms talks with Russia and said Kim's visit showed how isolated Moscow has become on the world stage.
But the head of Ukraine's military intelligence, Kyrylo Budanov, told Ukraine's NV Radio that North Korea had already been supplying Russia with weapons for more than a month.
"It was already a month and a half ago that everything was agreed and shipments began from North Korea," he said without giving further details.
Russia has joined China in opposing new sanctions on North Korea, blocking a US-led push and publicly splitting the UN Security Council for the first time since it started punishing Pyongyang in 2006.
Asked about military cooperation, Putin said Russia complied with international rules but that there were opportunities to explore.
The choice to meet at Vostochny Cosmodrome - a symbol of Russia's ambitions as a space power - was notable, as North Korea has twice failed to launch reconnaissance satellites in the past four months.
After showing Kim around a building where the Angara, Russia's new 42.7-metre space launch rocket, is assembled, Putin said Kim had shown a "great interest in rocket engineering" during the visit.
Ahead of his meeting with Putin, Kim signed the visitor book in Korean: "The glory to Russia, which gave birth to the first space conquerors, will be immortal."
BALLISTIC MISSILES
As Kim was making his way through the forests of Russia by train, North Korea launched two short-range ballistic missiles from an area near the capital, Pyongyang, into the sea off its east coast.
Kim had previously made just seven trips abroad in his 12 years in power, all in 2018 and 2019. He also briefly stepped across the inter-Korean border twice.
The make-up of Kim's delegation to Russia, with the notable presence of Munitions Industry Department Director Jo Chun Ryong, suggested an agenda heavy on defence industry cooperation, analysts said.
"In Korea, there is a proverb: good clothes are those that are new, but old friends are best friends. And our people say: an old friend is better than two new ones," Putin told Kim.
"This folk wisdom is fully applicable to modern relations between our countries."
