The Biden administration is concerned that a weakened Iran could build a nuclear weapon, White House National Security Advisor Jake Sullivan said on Sunday, adding that he was briefing President-elect Donald Trump’s team on the risk.Iran has suffered setbacks to its regional influence after Israel’s assaults on its allies, Palestinian Hamas and Lebanon’s Hezbollah, followed by the fall of Iran-aligned Syrian president Bashar al-Assad.For all the latest headlines follow our Google News channel online or via the app.Israeli strikes on Iranian facilities, including missile factories and air defenses, have reduced Tehran’s conventional military capabilities, Sullivan told CNN.“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 said.Iran says its nuclear program is peaceful, but it has expanded uranium enrichment since Trump, in his 2017-2021 presidential term, pulled out of