The Russian president said he was “satisified with the results” of talks with his North Korean counterpart, which he said spanned denuclearisation, sanctions, and the United States.
Mr Putin indicated he would share details of the summit with Donald Trump.
“There are no secrets,” he said, adding Mr Kim had encouraged him to explain the nuances of Pyongyang’s stance to the US president.
Pyongyang was ready to dismantle its nuclear programme but wants strong security guarantees backed by multiple countries in return, the Russian president said. He did not say what the guarantees should be.
“We - me and my colleagues - are satisfied with the results of the talks,” Mr Putin told reporters following the first of a two-day summit.
South Korea’s president, Moon Jae-in, said he believed the talks in Russia would play a “constructive role” in efforts to achieve lasting peace in the Korean peninsula.
In a statement, his office said it hoped the summit would ”lay a foundation for the resumption of North Korea-US talks and the promotion of denuclearisation”.
The Kremlin has long sought a meeting with the North Korean leader, with analysts saying Mr Putin is “desperate to be considered a person of significance on the Korean peninsula, and to use that in diplomatic games with Washington”.
Mr Kim accepted an invitation to visit Russia after talks with Mr Trump broke down in February without an agreement on sanctions or denuclearisation.
At the start of Thursday's talks, Mr Putin said he hoped the meeting “would help us better understand what should be done to settle the situation on the Korean Peninsula, what we can do together”.