"Those talks have to be real. They have to be based on them living up to their obligations, to include on proliferation, on nuclear weapons, on smuggling and other things," said Denis McDonough, President Barack Obama's chief of staff.
"So we'll judge them by their actions, not by the nice words that we heard," he said.
The National Defence Commission headed by North Korean leader Kim Jong Un issued a statement through state media proposing "senior-level" talks to ease tensions and discuss a peace treaty formally ending the Korean War.
Tensions have risen as a result of North Korea's launch of a long-range rocket in December and a nuclear test in February.
North Korea's offer is expected to be discussed in meetings this week in Washington involving US, Japanese and South Korean officials.
"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 UN resolutions, and "ultimately result in denuclearization," National Security Council spokeswoman Caitlin Hayden said in a statement.