The International Atomic Energy Agency has sent three more experts to Iran for talks on its nuclear program. The agency wants Iran to agree to more rigorous inspections of its nuclear facilities.

The IAEA says three more nuclear safeguard experts arrived Friday in Tehran, joining two colleagues who are holding technical discussions with the Iranian authorities.

The IAEA team plans several days of talks with counterparts from the Iranian atomic energy organization, which is building nuclear facilities and developing technology.

The agency plans to send another group of experts to Iran next week to explain the implications of signing the so-called additional protocol on nuclear inspections. The head of the IAEA, Mohamed ElBaradei, briefly visited Tehran earlier this week to urge the government to sign the protocol as a confidence building measure. The U.N. agency is trying to avoid a confrontation between Iran and western nations, which claim its nuclear program is designed to develop weapons.

The agency's spokesman, Mark Gwozdecky, who accompanied Mr. ElBaradei, says agreeing to the protocol would not mean that inspectors would suddenly be running all over the country.

"This is not Iraq where we had unlimited rights to go anywhere anytime," he said. "The protocol means that the state first of all has to provide us a wide variety of information on basically everything directly or indirectly related to nuclear, so that's an obligation that they don't have now.

"So they have to declare to us everything and then we have to make an assessment as to whether we're confident that there aren't illegal nuclear activities and then at that point once we have a base line where we understand that the country's program is entirely peaceful, then the protocol is implemented and the inspection procedures are only necessary if something comes to light that is justifying a special sort of inspection," added Mr. Gwozdecky.

Mr. Gwozdecky says the Iranians want to know what they would be signing up for.

Western diplomats in Vienna, speaking on the condition of anonymity, expressed concern and disappointment that Mr. ElBaradei's visit did not result in the immediate signing of the protocol. They fear the Iranians are stringing things out and say even if Iran signed the protocol now, it might take years before it could be fully implemented.

The United States believes Iran has a secret nuclear weapons program, something strongly denied by Tehran.

The United States is likely to press for tougher action against Iran if it does not agree to the protocol soon.

An IAEA board of governors meeting, scheduled for September, could refer the problem to the United Nations Security Council.