Washington ? Heightened activity detected by spy satellites around a North Korean nuclear plant has American intelligence analysts in disagreement: Is the reclusive communist government rushing to produce nuclear weapons or just bluffing?

Throughout January, American spy satellites have detected covered trucks apparently taking on cargo at the nuclear storage facility at Yongbyon, where spent nuclear fuel rods are stored, U.S. officials said Friday on condition of anonymity. When processed, enough plutonium could be extracted from the rods to make four or five nuclear weapons. The U.N. nuclear watchdog has said there are 8,000 rods.

White House spokesman Ari Fleischer would not comment on the intelligence, but warned officials in Pyongyang, North Korea’s capital, against taking “another provocative step” that “further isolates North Korea from the international community.”

Immersed in planning for a possible war against Iraq, the Bush administration has played down Korean developments of recent months even as North Korea continued to ratchet up the tension.

There is a broadening consensus in the administration that the reclusive communist regime is moving quickly down the path toward developing nuclear weapons, one senior defense official said. At the same time, another said that because North Koreans knew they were being watched, Pyongyang was also suspected of maneuvering to force Americans to the bargaining table.

“The fact that they’ve done this in broad daylight, as it were, suggests to me that this is part of the brinksmanship with the United States,” said Kurt Campbell, an Asia specialist at the Center for Strategic and International Studies.