The head of the U.N. nuclear agency began talks with Iranian leaders Wednesday during which he was expected to urge the government to allow unfettered inspections of its nuclear sites.

Mohamed ElBaradei (search), the chief of the International Atomic Energy Agency (search), has said he wants Iran to sign an additional protocol to the Nuclear Nonproliferation Treaty (search) that would give the agency's inspectors the right to visit any Iranian nuclear site without prior notice.

ElBaradei was also expected to urge the government to permit inspectors to take environmental samples at a location where it has allegedly enriched uranium — a process that can be used to produce nuclear weapons.

Iranian leaders said the visit sought to "build mutual confidence," state-run Tehran radio reported.

The United States suspects Iran (search) is trying to build a nuclear bomb, and has called for greater transparency on its nuclear program.

Iran denies it has ambitions to build an atomic bomb and insists its nuclear program is for generating electrical power particularly after its oil reserves run out. Iran is in the final stages of building its first nuclear power plant, based on Russian technology, outside the southern city of Bushehr.

Iran's Foreign Minister Kamal Kharrazi told ElBaradei that his government needed to convince the nation before signing the additional protocol, the official Islamic Republic News Agency reported.

"We need justifications to explain to the people and political parties that undertakings are in line with our national interests," IRNA quoted Kharrazi as saying.

Iran has said it would agree to inspections if it is granted access to advanced nuclear technology as a signatory to nonproliferation treaty and as an IAEA member. Iran accuses Washington of using its influence with other nuclear empowered nations to block the sale of such technology.

"Iran insists on its legitimate rights concerning the NPT (nonproliferation treaty) and as a sense of responsibility to fulfill its obligations and exercise transparency," Kharrazi was quoted as saying.

ElBaradei was scheduled to meet President Mohammad Khatami and the head of Atomic Energy Organization of Iran Gholamreza Aghazadeh later Wednesday.