North Korea reportedly did not make a firm promise to return to the six-way nuclear talks during the U.S. special envoy’s visit to Pyongyang.

A senior official at the U.S State Department said Friday that Pyongyang has yet to make any definitive statement on its return to the nuclear negotiations, adding that the U.S. is waiting for the North’s response on the matter.

The official said the ball is still in the North’s court and stressed that the other members of the nuclear talks would have no choice but to continue to implement sanctions against the North if Pyongyang refuses to come back to the talks.