The United States on Thursday warned allies and China to join President Donald Trump's new campaign to isolate the Iranian economy, vowing that Washington would "collapse this regime" in Tehran. Iran branded the US threats as "economic terrorism" and said they would fail. Under fire at home over the impact of the war and with crucial midterm elections looming, Trump had on Wednesday promised the "most crushing" economic operation ever against Iran. US Treasury Secretary Scott Bessent echoed the president's comments, doubling down on economic pressure on Tehran as Trump's unpopular war drags towards the six-month mark. "Any remaining tie to Tehran will hasten a nation's economic oblivion, whether that tie be purposefully constructed or willfully ignored," Bessent said on X. Read moreTrump says no Iran talks planned as UAE suspends trade with Tehran Neither Trump nor his Treasury chief has set out the measures they are planning against Iran. Bessent said he would give more details during a press conference on Monday. "We're kind of now in a new phase where the most effective tool that we have is the economic pressure that we can apply to them," Vice President JD Vance told a conservative podcast. "This is a delicate dance because" Iran will "try to apply economic pressure to us." Asked whether the United States would pressure China, Bessent told CNBC that "many conversations are best to have in private", but called on Beijing "to get with the programme". Chinese President Xi Jinping is due to visit the White House on September 24.