A nuclear nonproliferation conference in Moscow has ended without a separate meeting between the U.S. and North Korean envoys in attendance.

U.S. Special Envoy for North Korea Mark Lambert and Jo Chol-su, director-general of the North American department at the North's Foreign Ministry, attended the 2019 Moscow Nonproliferation Conference.

South Korea's top nuclear envoy Lee Do-hoon also attended the forum, but the three-day event closed Saturday without any meaningful talks between him and Jo or Lambert and Jo.

Lambert and Jo did engage in a brief five-minute chat during a reception Thursday evening, while the Korean envoys did not go beyond an exchange of greetings.