The US envoy aiming to restart six-party talks on North Korea's nuclear programme has headed home with no deal on when talks might resume.
Mr Kim says North Korea will not unilaterally disarm
But after two days of talks with North Korea, Christopher Hill said he hoped the talks could begin during December.
Pyongyang has ruled out unilaterally renouncing nuclear weapons without security guarantees, reports said.
North Korea detonated a nuclear device in October, leading to the imposition of international sanctions.
Speaking in China, where he met North Korea's Deputy Foreign Minister, Kim Kye-gwan, Mr Hill said it was vital that any restarted talks had a real chance of success.
"We've got to get North Korea off of this nuclearisation programme, because, unless they denuclearise, really nothing is going to be possible."
Mr Kim has said North Korea is ready for talks, which he said would be on an "equal level" following its 9 October nuclear test.
He appeared to reject Mr Hill's demand that Pyongyang renounce its nuclear weapons programme as a precondition.
South Korea's Yonhap news agency quoted Mr Kim as saying that North Korea would not unilaterally give up its nuclear weapons programme.
Instead, Mr Kim said the North stood by a previous agreement to "denuclearise" the Korean peninsula in exchange for security guarantees, the report said.
Earlier, Mr Hill insisted Pyongyang must renounce its weapons programme if new talks were to have any purpose.
"The purpose is to make sure that when we start the talks, that we really do make progress.
"The purpose of the six-party talks is not to talk, it's to achieve the denuclearisation of the Korean Peninsula."
Mr Hill said he had presented Mr Kim with ideas from the US on how North Korea could manage to disarm, and would now wait for a response.
The six-nation talks, which are hosted by China and also include South Korea, Japan and Russia as well as North Korea and the US, stalled a year ago after Pyongyang pulled out in protest at US financial sanctions imposed upon it.
North Korea's nuclear test on 9 October triggered international alarm and condemnation, and prompted the UN to impose financial and arms sanctions.
But at the end of last month, Pyongyang agreed to restart six-party talks at an informal meeting between Mr Hill and Mr Kim in Beijing.
While the resumption of talks has been welcomed by all parties to the talks, Japan warned at the time that they were conditional on North Korea giving up its nuclear weapons.