The Administration has urged Israel to sign the nuclear accord.

Mr. Mubarak did not say explicitly today that his country would support the permanent and unconditional extension of the nuclear accord, as the United States is pushing.

The nuclear accord, which expires this year, is up for renewal at an international conference beginning in April.

But there could be a crisis in the spring if South Korea refused to proceed with the nuclear accord and the North then threatened to back out of it.

Although North Korea later acceded to the nuclear accord, Pentagon officials acknowledged that they have little insight as to who is actually running the country.

By agreeing for now to remain in the nuclear accord, North Korea has eased the United States' most immediate concern.

Despite the anxiety in Seoul, experts say the major obstacles to a nuclear accord have not yet been overcome.

A second launching would probably derail any chance that Congress would approve further participation in the nuclear accord, Administration officials fear.

Mr. Richardson arrived in North Korea early Saturday for a two-day visit to examine the human rights situation there and discuss the nuclear accord.