The UN nuclear watchdog is aware of all of Iran’s activities, the head of country's atomic energy organization said on Friday, a day after the atomic agency's Board of Governors demanded an explanation for traces of uranium at three undeclared sites.

The resolution, which was drafted on Thursday by the United States, Britain, France and Germany, said it was "essential and urgent" that Iran explain the origin of the uranium particles and more generally give the International Atomic Energy Agency all the answers it requires.

“Iran has not done and will not do anything that the agency is not aware of,” Mohammad Eslami, chief of Iran’s atomic energy organization was quoted as saying by the semi-official ILNA news agency.

“Our activities are all within the framework of regulations,” he said, adding: “There is no problem about safeguards, which are the criterion of our cooperation.”

Resolution of the so-called "safeguards" investigations is critical to the UN agency, which seeks to ensure parties to the Nuclear Non-Proliferation Treaty are not secretly diverting nuclear material which they could use to make a weapon.

"They have been pressuring Iran for 20 years, but negotiations have continued," said Eslami.

In June, Iran removed IAEA monitoring equipment including surveillance cameras installed under its 2015 deal with world powers to curb its disputed uranium enrichment program.

"The political goals of the founders of this anti-Iranian resolution will not be realized but it could impact the constructive relations between Tehran and the Agency," Iran's envoy to the IAEA, Mohsen Naziri, said on Thursday, according to Iran's state media.