TEHRAN, Iran -- Iran promised to prove by mid-May that it doesn't want to build nuclear weapons, the chief U.N. nuclear inspector said Tuesday.

Mohamed ElBaradei, head of the International Atomic Energy Agency, said Iranian leaders assured him they know they must cooperate with the Vienna-based nuclear watchdog. The international community has become increasingly suspicious that Tehran is hiding evidence about its nuclear program.

"We agreed that we need to accelerate the process of cooperation," ElBaradei said.

Gholamreza Aghazadeh, head of the Atomic Energy Organization of Iran, said at a news conference with ElBaradei that the country would voluntarily suspend its centrifuge work starting Friday.

The statement was confusing because Iran announced on March 29 it had stopped building centrifuges for uranium enrichment. Such ambiguities are among the reasons the international community has increasingly doubted Iran's claims that its nuclear program is peaceful.

Following talks with Iranian officials, ElBaradei said the Islamic state promised to clear up any suspicions by mid-May -- ahead of a June deadline. He said Tehran has promised to give him all information regarding its present and future nuclear activities.

'Without further delay'

"We will do our best to complete our task without further delay," he said. "A lot of that depends on the cooperation we get from Iran ... and other countries like Pakistan, where some of the equipment came from."

ElBaradei welcomed Aghazadeh's announcement on centrifuges and said a new team of inspectors would come to Tehran on Monday to verify that all uranium enrichment activities have been stopped.

Aghazadeh said he expected all questions about Iran's nuclear program would be settled by June, at the next meeting of the IAEA's board of governors.

Iran wants "to bring this case to a close" as quickly as possible, Aghazadeh said. "We will do our best (for) ... our relationship with the agency to be normalized," he said.

ElBaradei, who was to return to Vienna on Wednesday, said earlier that he would address two key points with top Iranian officials: the origins of traces of highly enriched uranium found in Iran last year, and details on Iran's advanced P-2 centrifuges -- equipment that could be used to enrich uranium for use in a weapon.

Iran says its nuclear program is geared only toward producing electricity. The United States and other nations contend it is masking a covert effort to build a nuclear weapon, and an IAEA resolution last month censured Iran for hiding suspicious activities.

On Sunday, Iran denied it has moved any nuclear activity to easier-to-conceal sites.

Iranian officials were responding to alleged intelligence from the United States and an unnamed country suggesting that within the past year, Iran had moved nuclear enrichment programs to more remote locations.

Iran's nuclear ambitions first came under international scrutiny last year, when the IAEA discovered that Tehran had not disclosed large-scale efforts to enrich uranium, which can be used in nuclear warheads. Finds of traces of weapons-grade uranium and evidence of suspicious experiments heightened concerns.

"There is a growing feeling that the Iranians are playing games instead of honoring pledges of full disclosure," one diplomat said Monday, speaking on condition of anonymity.

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Associated Press Writer Ali Akbar Dareini in Tehran contributed to this report.

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