The United States and South Korea have responded coolly to North Korea’s offer of high-level talks with Washington.
North Korea will be judged “by its actions and not its words”, a US spokeswoman said.
The North proposed talks on “regional peace” with the US on Sunday, but said there should be no “preconditions”.
Last week, planned talks between Pyongyang and Seoul fell through following disagreement over which delegates should attend.
Regional tensions were raised earlier this year after Pyongyang conducted its third nuclear test and threatened to attack South Korean and US targets in the region.
In recent weeks rhetoric from Pyongyang has softened, but US officials appeared skeptical of its offer.
“Our desire is to have credible negotiations with the North Koreans, but those talks must involve North Korea living up to its obligations to the world, including compliance with UN Security Council resolutions, and ultimately result in denuclearization,” US National Security Council spokeswoman Caitlin Hayden said.
North Korea had to live up to its obligations on nuclear proliferation, Denis McDonough, chief of staff to the US president, told US broadcaster CBS news.
“We’ll judge them by their actions, not by the nice words that we heard yesterday,” Denis McDonough said.
“They’re not going to be able to talk their way out of very significant sanctions they’re under now,” he added.
North Korea’s powerful National Defense Commission had also suggested that any talks on reducing nuclear weapons would need to include American weapons as well as North Korean ones.
South Korea’s Unification Ministry said its stance on talks was the same as the US.
“The window of dialogue is open but that the North should take concrete steps first,” ministry spokesman Kim Hyung-seok said.
North Korea has reneged on deals with the US on several occasions in the past. In February 2012, it agreed to a partial freeze in nuclear activities and a missile test moratorium in return for US food aid.
However, it announced plans for a rocket launch in March that year – something the US called a disguised test of banned missile technology – leading the US to suspend its plans for food aid.
The US, Japan and South Korea are scheduled to meet in Washington on Wednesday to discuss resuming six-party talks on nuclear disarmament with North Korea.
The six party talks are the agreed forum for discussing North Korean denuclearization, but have been stalled since 2009.
The US also wants a commitment to denuclearization to be a precursor to negotiations with North Korea.