President Donald Trump has not backed an idea for a 45-day ceasefire in which Iran would either reopen the Strait of Hormuz or face major attacks on its civilian infrastructure. The proposal is being discussed by the U.S., Iran, and a group of regional mediators. In a social media threat, Trump threatened to strike Iranian bridges and power plants if Iran did not comply with the demands. The new deadline is 8 p.m. ET on Tuesday.