There was no official word from Iran on Monday that it had resumed nuclear research, despite goverment pledges as recently as that morning that it would do so. Inspectors from the International Atomic Energy Agency arrived in Tehran on Saturday to remove seals they had affixed to the nuclear research sites more than two years ago. They were expected to complete their task Monday and Iran had vowed it would immediately resume work. "As announced, nuclear research will be resumed in Iran today in the presence of International Atomic Energy Agency representatives," government spokesman Gholamhossein Elham told a weekly news conference in the morning. Throughout the day, state media continued to report that the seals would be broken and research would begin. But the day finished with no word of any developments. It was not clear why Iran might have delayed its pledge, though at least one official - Hossein Entezami of the Supreme National Security Council - had said recently that the resumption could come either Monday or Tuesday.