The top Asia hand at the US National Security Council, Dennis Wilder, said North Korea was not "off the hook" on fully declaring its atomic programs, but that proliferation issues would be "handled in a different manner".
The concession came as South Korean President Lee Myung-bak proposed the creation of the first liaison offices in the capitals of the two Koreas, which are technically in a state of war.
On the weapons front, US Secretary of State Condoleezza Rice, in an apparent concession to Pyongyang, indicated the entire overdue declaration might not be made public. She hinted US sanctions against North Korea could be removed even before the hardline communist state's nuclear programs or proliferations activities were verified independently.
North Korea has been pushing the US to remove it from the black list of state sponsors of terrorism. Dr Rice said the document incorporating North Korea's proliferation activities could be kept private, allowing Pyongyang to save face.
Washington is eager to see the denuclearisation drive completed before President George W. Bush leaves office in January next year. The North tested a nuclear bomb in October 2006.