"The North Koreans said they would return but did not give us a time," US State Department spokesman Sean McCormack said, referring to a meeting on Monday with American diplomats at the North Korean mission to the United Nations in New York.
His statements followed similar remarks on Tuesday at the White House by Scott McClellan, President George Bush's chief spokesman.
North Korea's UN ambassador Pak Gil Yon confirmed to Associated Press Television News that he met State Department envoy Joseph DiTrani on Monday morning.
"We discussed the matters of common interest, including that of the bilateral or six-party talks," he said, but refused to comment further.
In New York, China's United Nations ambassador said six-nation talks were likely to resume in the next few weeks in Beijing.
Ambassador Wang Guangya said the talks were the best way to resolve the nuclear standoff and said he was hopeful progress would be made.
Mark Malloch Brown, chief of staff to UN Secretary-General Kofi Annan, when told of the possible resumption of talks, gave a thumbs up and said: "Great!"
The other nations taking part in the talks are South Korea, Japan and Russia.
"It is best for North Korea to participate in six-way talks"
Japanese prime minister
A spokesman for Japan's Foreign Ministry said North Korea's return to the talks would be welcome because it would serve the interests of all the nations.
China was especially helpful in the breakthrough, spokesman Akira Chiba said, because "China has many contacts with North Korea, and I believe that they are in a position to communicate with them better than the other parties".
Prime Minister Junichiro Koizumi said separately: "It is best for North Korea to participate in six-way talks."
Negotiations over Pyongyang's nuclear programme have been in suspension for nearly a year.
McCormack said the US thinks the six-party talks represent the only format for negotiations.
He said the bilateral talks in New York are a way to keep in touch but are not a format for negotiations.
Earlier, McClellan said North Korea was committed to six-nation talks but that the representatives of Pyongyang in New York gave no indication as to when they would return to the negotiating table.