After two years of difficult investigations and increased suspicions, the International Atomic Energy Agency demanded Saturday that Iran cease all nuclear activities that could provide a cover for a secret weapons program.

In a resolution that took six days and dozens of meetings to negotiate, the 35-member board sent a strong message to Tehran but fell short of including key demands that the Bush administration was seeking in order to move the issue into the U.N. Security Council in the coming weeks. The final text said the board would decide what follow-up steps to take when it reconvenes on Nov. 25.

U.S. negotiators said they would insist then that the board move the issue into the council, which has the authority to impose sanctions or an oil embargo if it chooses. European negotiations refused to predetermine the outcome of November's meeting, hoping IAEA inspectors will complete their investigation by then and Iran will have met the board's terms.

"This resolution sends an unmistakable signal to Iran that continuing its nuclear weapons program will bring it inevitably before the Security Council," said Ambassador Jackie W. Sanders, who led the U.S. delegation.

The resolution, which went through a series of last-minute changes after a week of contentious debate, calls on Iran to immediately end its uranium enrichment program. But it also notes the rights of states to carry out such activities in the pursuit of peaceful nuclear energy.