A senior North Korean official has said the North does not intend to abandon its nuclear programme when it returns to talks on the subject, reports say.
Deputy foreign minister Kang Sok-ju said the North had not tested a nuclear weapon last month to then get rid of them, according to Japanese media.
North Korea recently agreed to return to stalled multi-national talks, which could resume next month.
Japan had said Pyongyang must renounce its nuclear plans before talks restart.
"Why would we abandon nuclear weapons?" Mr Kang was quoted by Japan's NHK television as saying. "Are you saying we conducted a nuclear test in order to abandon them?"
When asked if North Korea planned to demand the US lift financial sanctions imposed a year ago, Mr Kang replied: "Of course".
Mr Kang's comments were made to reporters as he passed through Beijing airport on his way home after a private trip to Russia.
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 a meeting of North Korean, Chinese and US diplomats in Beijing.
The talks - which are ultimately aimed at halting North Korea's nuclear ambitions - stalled a year ago after Pyongyang pulled out in protest at US financial sanctions imposed upon it.
The resumption of talks was welcomed by both South Korea and Russia, which along with the US, China and Japan make up the partners in the talks with North Korea.
But Japan's Foreign Minister Taro Aso said the talks were "conditional on North Korea not possessing nuclear weapons", NHK reported at the time.