The head of the UN nuclear watchdog urged Iran on Tuesday to provide more cooperation in the investigation into Iran's nuclear activities.

"I would ask Iran to support the agency's efforts to further pursue its investigation of the Lavizan-Shian and Parchin sites," said Mohamed ElBaradei, secretary general of the International Atomic Energy Agency (IAEA).

ElBaradei, who won his third term as the head of the IAEA on Monday, said that the discussion was under way for reaching an agreement on modalities.

The IAEA also wanted its experts to visit "areas of interest" at Parchin.

Parchin and Lavizan are among the sites where the United States suspects Iranian scientists have conducted research related to the development of nuclear weapons.

Iran denied the allegation, saying that it has no interest in nuclear weapons.

ElBaradei said that the agency had continued to monitor all aspects of Iran's voluntary suspension of enrichment-related and reprocessing activities.

"The agency is making progress on one of two key remaining issues: namely, the origin of the low- and high-enriched uranium contamination on equipment at various locations in Iran," ElBaradei said in a statement.

ElBaradei, however, accused Iran of not providing the IAEA with full documentation of its centrifuge program, the second major outstanding issue the agency has been unable to resolve.

"We have continued to press for additional documentation regarding offers of equipment made to Iran," ElBaradei added.

Source: Xinhua