The outgoing Biden administration is briefing President-elect Donald Trump's team on the growing risk of Tehran pursuing the development of a nuclear weapon, US National Security Advisor Jake Sullivan said on Sunday.

There is now a "real risk" that Iran will revise its position that "we're not going for a nuke," Sullivan told CNN.

"It's a risk we are trying to be vigilant about now. It's a risk that I'm personally briefing the incoming team on," Sullivan added.

Since May, top Iranian officials including Supreme Leader Ali Khamenei's adviser, Kamal Kharrazi, have warned that if Iran's nuclear installations are attacked, the Islamic Republic will shift its nuclear doctrine. So far, Tehran has been insisting that its nuclear program is entirely peaceful, in spite of having exceeded international limits on uranium enrichment and accelerating its nuclear program.

In October, 39 lawmakers called for changing the nuclear doctrine without mentioning an attack on nuclear facilities but citing tensions with Israel.

The calls for the pursuit of nuclear weapons have grown in Iran following the Israeli airstrikes destroying the Islamic Republic's air defense batteries.

"It's no wonder there are voices (in Iran) saying 'Hey, maybe we need to go for a nuclear weapon right now... Maybe we have to revisit our nuclear doctrine'," Sullivan told CNN, referring to the decrease in Tehran's "conventional capabilities" following Israeli air raids.

"The Israeli military believes that Iran — isolated after the fall of the Bashar al-Assad regime and the weakening of its main proxy group Hezbollah in Lebanon — may push ahead further with its nuclear program and develop a bomb as it scrambles to replace its deterrence," The Times of Israel reported earlier this month citing military officials.

Following the weakening of Iran's proxy groups in the Middle East and the dramatic fall of the Assad government in Syria, the IDF believes there is an opportunity to strike Iran’s nuclear facilities, and the Israeli Air Force has therefore continued to increase its readiness and preparations for such potential strikes in Iran, the report said.