US envoy Christopher Hill on Monday warned North Korea against provoking the international community with a nuclear test, urging the secretive state to return to stalled talks on its atomic programme. "The DPRK (North Korea) does not seem as enthusiastic as we are about pursuing a diplomatic track, and obviously this is a very big problem for the six-party process," he told reporters in Tokyo at the start of a regional tour. "There is no reason for the DPRK to stay away from the diplomatic process and my government is very much committed to these talks," said Hill, referring to the North by its official name, the Democratic People's Republic of Korea.The US assistant secretary of state for East Asia and Pacific affairs voiced concern about media reports that Pyongyang, which claims to have built nuclear weapons, may be preparing an underground nuclear test. "I think all governments in the world have made very clear that it would be a very unwelcome development, and that the DPRK should really think long and hard for it to take such a provocative step," he added. "I hope the DPRK will understand that their future lives are not with these tests but by coming to the negotiating table and implementing the September agreement," he said.