The head of the UN nuclear watchdog said Tuesday that "intrusive inspections" are an arm that could be used against Syria because of its refusal to give access to suspect sites.

The International Atomic Energy Agency (IAEA) wants access to get to the Dair Alzour desert site that was bombed by Israel in 2007 and others in Syria, its director general Yukiya Amano said.

Syria is a close ally of Iran, which already faces four rounds of UN nuclear sanctions, and the atomic activities of the Damascus government are the subject of growing international suspicion.

"In Syria, special inspection is of course one of the options but for now I am continuing to request Syria to provide access and will continue to do so for now. For the future, as I said: I am open," Amano told the Council on Foreign Relations in New York.

The IAEA chief can ask the agency board for special "intrusive inspections" and Syria would be referred to the UN Security Council if it failed to comply.

He said the process has only been used in the past against North Korea, which is also the target of UN nuclear sanctions, and Romania after they refused inspections.

Amano said there were "other tools," but insisted "nothing has been decided."

"There has not been progress but for now I keep on asking Syria to accept inspectors at the site of Dair Alzour and other locations," he added.

IAEA inspectors went once to Dair Alzour and were allowed to take samples.

"We found that they are particles of man-made uranium. But up to today we cannot identify what is the origin," he said.

"Judging from the information that we have, we think that it is possible, or quite possible, that it was a reactor."

The other suspect sites include a miniature research reactor near Damascus.

Some observers have said Amano has taken a tougher line than his predecessor, Mohamed ElBaradei, in the nuclear standoff with Iran, and particularly with its IAEA ambassador, Ali Asghar Soltanieh. Iranian officials have accused Amano of bias.

"There is nothing personal at all, but the situation is that Iran is not implementing the Security Council resolutions and cooperation is not sufficient and we cannot confirm that all the activities in Iran are peaceful activities," Amano said.

"There is certain reactions from Iran and I don't think that it is anything personal." He said that "there is a good communication line" with Iran.

Thousands of computers in Iran were infected by the Stuxnet virus this year, but Amano said inspectors had seen nothing "irregular" in the Iranian nuclear program, which the West says is aiming to produce a nuclear bomb.

Iran insists that its research is peaceful. Iran and the international powers -- Britain, China, France, Germany, Russia and the United States -- could hold new nuclear talks as early as November 23, a European diplomatic source has said.

Amano said it was also important for new international talks on North Korea's nuclear weapons drive. He described events in North Korea as "very bad."

The United States, China, Russia, Japan and South Korea had been in talks with North Korea. But the last meeting with the isolated North was in December 2008 and it has since withdrawn from the negotiations.

There have been no IAEA inspectors in North Korea since April 2009. "There are also allegations that they are cooperating with other countries. This is a very serious situation," Amano declared.