The head of the U.N. atomic agency on Thursday shook off suggestions of pro-U.S. bias, asserting that his investigation of Iran's nuclear program was factual and objective.

Yukiya Amano was responding to his description as being "solidly in the U.S. court" in an American diplomatic cable, part of the latest batch of confidential information released Sunday by Wikileaks website.

Amano refused to directly comment on the cable, sent around the time of his election last year as the head of the International Atomic Energy Agency, saying it would be inappropriate to give reaction to a confidential diplomatic dispatch.

But he told reporters that his reporting was factual, saying "I will continue to make my reports based on facts."

"I said what I should have said as director-general of the IAEA," he said.

Iran and its allies in the camp of developing nations regularly criticize Amano, claiming the language in his reports on the IAEA's attempts to oversee Tehran's nuclear program is skewed and departs from what they say was the more objective style of his predecessor, Mohamed ElBaradei.

In opening statements to a meeting of the 35-nation IAEA board earlier in the day, he told delegates that "Iran has not provided the necessary cooperation to permit the agency to confirm that all nuclear material in Iran is in peaceful activities."

He also warned about "concerns about possible military dimensions" to Tehran's nuclear program — phraseology similar to that in his reports that Tehran and its allies object to.

Amano's comments, coming four days before scheduled talks in Geneva between representatives of Iran and six world powers, reflected international concerns about Tehran's refusal to freeze uranium enrichment and heed other U.N. Security Council demands to curb its nuclear program.

Iran says it has a right to enrich to make fuel for an envisaged network of nuclear reactors under the Nonproliferation Treaty. But because of the Islamic Republic's nuclear record — its enrichment program and other activities were kept secret until they were revealed by others — there are fears it could turn the program toward churning out weapons-grade uranium used in the fissile core of warheads.

An EU statement delivered at the meeting faulted Iran for "failing to cooperate fully with the IAEA" and expressed concern that Tehran's stonewalling has prevented the IAEA from probing suspicions that the Islamic Republic had engaged in past experiments "related to possible military dimensions."