Iran on Saturday opened the gates to a key uranium conversion facility to visiting diplomats and journalists in an effort to show that its disputed nuclear program is peaceful and not a cover for nuclear bomb making.

The visit to the Isfahan plant in central Iran was the first such tour since Iran resumed uranium conversion in August 2005. The U.N. Security Council slapped economic sanctions on Iran on Dec. 23 over the country's refusal to halt uranium enrichment, which can be used for making weapons.

Click here for FOXNews.com's Iran Center.

The visit also came ahead of a U.N. deadline for Iran to stop the enrichment. If Tehran doesn't comply by the end of the 60-day period stipulated by the U.N., the Security Council will consider new measures beyond the economic sanctions.

The United States and several of its Western allies believe that Iran is using the nuclear program to produce an atomic weapon — charges Iran denies, saying its aim is to generate electricity.

The diplomats visiting the plant came from Sudan, Cuba, Egypt, Malaysia and Algeria. They represented the Arab League and two groups of developing nations known as the Nonaligned Movement and the G-77 — organizations that have asserted the rights of members to pursue national interests unfettered by Western countries.

The plant at Isfahan, 255 miles south of Tehran, is responsible for an early stage of the nuclear fuel cycle, turning yellowcake uranium into uranium hexaflouride gas, or UF-6, the feedstock for enrichment.

International concerns have recently focused more on the facility in Natanz, where uranium can be enriched using cascades of centrifuges. Only highly enriched uranium can be used for bomb-making.

But Iranian officials on Saturday's tour talked only of the program's peaceful purposes, which Iran is determined to pursue.

Ali Ashgar Soltanieh, head of Iran's delegation to the U.N. nuclear watchdog agency — the International Atomic Energy Agency — said the message of the visit was to show "that Iran is determined to continue its peaceful nuclear activities."

"This is an opportunity to see for yourselves what is going on and get first hand information about the activities here," Soltanieh told the diplomats and dozens of reporters.

The visitors saw several areas of the Isfahan facility, including two cameras installed by the IAEA to monitor activity where uranium gas is produced.

Soltanieh said the two cameras, which take photos every two minutes, are in place according to Iran's obligations under the Nonproliferation Treaty.

They are the only cameras at Isfahan. Iran removed others here when it stopped allowing the IAEA to conduct snap inspections, a measure it took after the agency referred it to the Security Council last February. IAEA inspectors visited the Isfahan facility twice in January.

Soltanieh said the tour was "an opportunity to see that the IAEA has full surveillance control over the activities of this facility."

At the end of the tour, Soltanieh told the visitors that all the 250 tons of UF-6 gas which Iran produced in 2006 have been safely stored at Isfahan's underground tunnels, but refused to answer questions about where the tunnels were located in the plant.

Anti-aircraft guns and radar stations surround the facility, much of which is built underground to protect it from airstrikes, which became a concern for Iran after Israel hit Iraq's main reactor in 1981.

On Friday, a top Iranian nuclear official said that U.N. inspectors have set up cameras at Natanz that would allow them to monitor the activity there. Centrifuge hookup is expected to start at Natanz next week.

Diplomats accredited with the IAEA in Vienna, Austria, said that hundreds of technicians and laborers have been "working feverishly" at Natanz over the past few weeks, setting up piping, control panels and electric cables before the centrifuge hookup.

But a U.N. official in Vienna, where the IAEA is based, said that Iran had met only some of the world body's requests for installing monitoring cameras at Natanz's underground site.

Tehran already has cascades of 164 centrifuges installed above ground at Natanz and has announced plans to operate 3,000 centrifuges below ground there, enabling it to speed up production of nuclear fuel.

Click here for FOXNews.com's Iran Center.