North Korea’s chief nuclear negotiator met informally with U.S. representatives in Mongolia late last week, he said Monday.

Ri Yong Ho, the North Korean envoy to the stalled Six Party Talks, was asked after his arrival at a Beijing airport whether he had met informally with U.S. experts while in the east-central Asian nation, to which he answered in the affirmative. However, he provided no further details before being leaving with a vehicle belonging to the North Korean embassy.

The talks in the Mongolian capital of Ulaanbaatar took place Friday, apparently aimed at restarting the Six Party Talks discontinued since