A second summit will bring U.S. President Donald Trump and North Korean leader Kim Jong Un face-to-face in Vietnam.
Across two days, both leaders will be in the capital of Hanoi.
The Associated Press reports Moscow was asked for expertise ahead of the meeting.
The two are also expected to resume talks from their last summit in Singapore last June.
Both leaders expressed their support on trade and military, without reaching a solid agreement on North Korea’s de-nuclearization.
Trump said his country would be “happy” if Un continues to cease efforts on nuclear weapon developments, The Guardian reports.
While Trump flies to Hanoi in a private jet, Un was photographed travelling through China in an armoured train.
According to the BBC, Trump took to Twitter again to encourage North Korea’s de-nuclearization, tweeting the country could be “one of the great economic powers anywhere” in the planet.