Administration officials also said they had not decided whether to issue an ultimatum before acting. One official said the administration did not foresee a new diplomatic appeal to Iraq, like the one the U.N. secretary-general, Kofi Annan, made in February to avert a U.S.-led strike.

While the administration had refused to discuss any timetable for action, there are external factors that could affect decisions in the days ahead. A significant one is the president's schedule. He plans to leave the United States on Friday for a nine-day trip to Asia.