Supreme leader Ayatollah Ali Khamenei said on Friday Iran is not seeking atomic weapons despite global condemnation after a UN report expressed concern it is trying to develop a nuclear warhead.

As France and Germany called for fresh sanctions on Iran, the Islamic republic's envoy to the UN atomic watchdog dismissed as "baseless" the leaked report.

In Moscow Russian Deputy Foreign Minister Sergei Riabkov said meanwhile his country is opposed to "crippling sanctions" against Tehran.

Khamenei, the country's commander-in-chief, said Iran's religious beliefs meant it was against the use of nuclear weapons.

"Recently some Western and US officials have been repeating some outdated and nonsensical comments that Iran is seeking to build nuclear weapons," he said.

"Iran will not get emotional in responding to these nonsensical comments, since our religious beliefs are against the use of such weapons," he told commanders at the launch of Iran's first domestically made naval destroyer in the Gulf.

"We in no way believe in an atomic weapon and do not seek one."

International Atomic Energy Agency chief Yukiya Amano, in a blunt first report to the watchdog's board of governors on Thursday, expressed concern Iran might be seeking to develop a nuclear warhead.

"The information available to the agency... raises concerns about the possible existence in Iran of past or current undisclosed activities related to the development of a nuclear payload for a missile," Amano wrote.

Ali Asghar Soltanieh, Iran's envoy to the IAEA, said the documents cited in the report were "fabricated and thus do not have any validity."

"I have also said many times that when they showed these documents to us none of the documents had any confidential or secret stamps on them," Soltanieh said.

Soltanieh repeated Tehran's stance that Iran's nuclear programme was peaceful, insisting that Iran "will never halt its peaceful nuclear activities nor stop its cooperation with the agency."

Western powers suspect Tehran is enriching uranium to make nuclear weapons, as the material in highly pure form can be used in the core of a atomic bomb.

Tehran has been slapped with three UN Security Council resolutions demanding a halt to its controversial uranium enrichment.

The IAEA report raised concern in France and Germany.

German Chancellor Angela Merkel's spokesman Ulrich Wilhelm said it "confirms the great concerns that the German government has had for a long time about Iran's nuclear programme."

"Our hand is still stretched out... but the continued defiance towards the IAEA, to UN resolutions and Iran's dangerous policies in general oblige the international community to take the path in New York towards further sanctions against the regime in Tehran," Merkel's spokesman said.

German Foreign Minister Guido Westerwelle echoed US Vice President Joe Biden saying he was confident that China, seen as the least keen on new sanctions among permanent UN Security Council members, would come on board.

"I have the firm impression that China sees the prospect of Iran having nuclear weapons as unacceptable," Westerwelle said.

In Paris, foreign ministry spokesman Bernard Valero said the report shows "how urgent it is to act with determination to respond to Iran's lack of cooperation."

The Russian deputy foreign minister meanwhile insisted that Moscow was against the imposition of "crippling sanctions" on Iran as demanded by Israel.

"The term 'crippling sanctions' is totally unacceptable to us. The sanctions should aim at buttressing the regime of non-proliferation," Sergei Riabkov said, according to Interfax news agency.

According to the IAEA report, inspectors verified that none of Iran's declared nuclear material had been diverted.

But it also said: "Iran has not provided the necessary cooperation to permit the agency to confirm that all nuclear material in Iran is in peaceful activities."

Earlier this week Israeli Prime Minister Benjamin Netanyahu was in Moscow, which is believed to wield significant influence with Tehran, and had asked Russia to help slap "biting" sanctions on the Islamic nation.

Meanwhile in the United States a key lawmaker said Washington should impose an embargo on gasoline deliveries to Iran in order to halt the Islamic republic's nuclear drive.

"The time is running out," said Representative Mark Kirk, co-chair of the bi-partisan House Iran Working Group, pointing to the IAEA report, and adding that UN sanctions failed to yield results.