The Wall Street Journal reported on Tuesday that the head of the UN's atomic agency, Rafael Grossi, has been given "round-the-clock" security protection following an Iranian threat.

The report said that Grossi received protection after Austria, where the UN's International Atomic Energy Agency (IAEA) is based, received information of a threat to the agency chief.

A person familiar with the matter told the Wall Street Journal that the threat came from "Iran-linked individuals," though the IAEA spokesman said the agency "cannot confirm where the specific threat came from."

"Iran accused Grossi of helping spark Israel's 12-day war in June, saying that his reports on Iran's nuclear work were biased and spread baseless concerns about Iran's nuclear activities. Top Iranian officials called for him to be put on trial and ousted from his job," the report said. Iran specifically cited a report where Iran's lack of a response meant the IAEA could not validate that Tehran's nuclear program was entirely for peaceful purposes.

A senior aide to the Iranian Supreme Leader Ayatollah Ali Khamenei said in June that the Islamic Republic will "deal with Grossi" once the war is over.