Ri Yong Ho, North Korea’s top nuclear negotiator on Monday said he explained North Korea’s recent proposal on the moratorium on nuclear tests to the U.S. at an informal two day meeting in Singapore.

The North Korean negotiator met with former U.S. special representative for DPRK policy Stephen Bosworth, former deputy nuclear negotiator Joseph DeTrani and Tony Namkung, former deputy director at Berkeley’s Institute for East Asian Studies, none of whom attended the meeting in an official capacity.