White House National Security Adviser Jake Sullivan said Sunday evening that the Biden administration is concerned about a weakened Iran seeking to acquire a nuclear weapon, adding that he is briefing President-elect Donald Trump's team on the danger.

Washington says Iran's influence in the Middle East has suffered setbacks after Israeli attacks on Lebanon's Hezbollah and the subsequent fall of President Bashar al-Assad's regime in Syria.

Sullivan told CNN that Israeli strikes on Iranian facilities, including missile production plants and air defenses, had reduced Tehran's conventional military capabilities.

"It's not surprising that there are voices in Iran saying, 'Maybe we should now pursue a nuclear weapon, maybe we should rethink our nuclear doctrine,'" Sullivan added.

uranium enrichment

Iran says its nuclear program is peaceful, but it has expanded uranium enrichment since Trump, during his first term, withdrew from an agreement between Iran and Western countries that aimed to curb Tehran's nuclear ambitions in exchange for easing sanctions on Tehran.

Sullivan said there was a risk that Iran would abandon its pledge not to possess nuclear weapons.

"This is a risk that we are now vigilant about. I am personally working to brief the new president's team on this risk," he added, stressing that he is also consulting with Israel on the issue.

Trump, who takes office on January 20, may resume a hardline policy toward Tehran by tightening sanctions on Iran's oil sector.

Sullivan said Trump would have the opportunity to continue diplomatic efforts with Tehran, given Iran's "weakened state."

"He may change his position this time, given the situation Iran finds itself in, and actually reach a nuclear agreement that limits Iran's nuclear ambitions in the long term," he added.