The Kremlin hasn't been front and center in discussions about North Korea's nuclear arsenal — but given its long ties with Pyongyang, Moscow probably can't be ignored in any potential peace deal.

Moscow, with the Kremlin in the background.

"Despite its relatively low public profile as a player in the North Korea negotiations, Russia's behind-the-scenes ability to throw a wrench in the process should not be underestimated," Elizabeth Economy, director of Asia studies at the Council on Foreign Relations, said in a Thursday note.

President Vladimir Putin's government plays "a critical role as a behind-the-scenes negotiator, spoiler, and unholy ally," so it shouldn't be sidelined in nuclear negotiations, she said.

Putin has the ear of both Pyongyang and Seoul, thanks to years of steady relations with both neighbors. Moscow has attempted to play the role of honest broker in the past by promoting inter-Korean diplomacy.

Days after Russian Foreign Minister Sergei Lavrov visited North Korea last week, the Kremlin invited ruler Kim Jong Un to Moscow.

Like China, Moscow has its own interests on the Korean Peninsula, and it will be watching closely to see how next week's talks between President Donald Trump and Kim affect its objectives.

This week, Putin praised Trump's decision to hold the June 12 summit as "very brave and mature."