US Treasury Secretary Scott Bessent's comments underscored how Trump is shifting to economic rather than military pressure on Tehran as his unpopular war drags toward the six-month mark.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."It is going to work in Iran and we are going to collapse this regime," Bessent told US broadcaster CNBC.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.But Bessent underlined that Washington expects both allies and rivals to join in."This is going to be the greatest coordinated economic isolation in the history of the world. And we are going to them and saying you are either with us or against us," he added in a message to allies.Asked whether the United States would pressure China, Bessent said that "many conversations are best to have in private," but called on Beijing "to get with the program."Chinese President Xi Jinping is due to visit the White House on September 24.'Crimes against humanity'