President Donald Trump announced on Wednesday that the U.S. was launching “economic warfare and isolation on an unprecedented scale” against Iran, threatening to take aggressive action against foreign entities and businesses engaging economically with Tehran.

“No one has given the Islamic Republic of Iran a greater opportunity to make a Deal than me,” Trump wrote on Truth Social, but Tehran has “failed to take it.” 

“Therefore, today, I am announcing the MOST CRUSHING ECONOMIC OPERATION EVER TAKEN AGAINST ANY COUNTRY,” he wrote.

Trump warned of broad “economic consequences” for those assisting Tehran’s economy, adding, “You know who you are.” While he did not explicitly name the measures the U.S. would take, his announcement came following his threat of U.S. military action against Oman earlier this week over potential interference in U.S. negotiations with Iran.

Calling the initiative an “economic D-Day,” Trump urged global allies to join Washington in isolating Tehran.

“These maniacs are on the ropes, and these HISTORIC MEASURES will cripple them and their ability to project terror worldwide,” Trump wrote, vowing once again that Iran will never have a nuclear weapon. 

While senior White House officials indicated earlier this week that talks between the U.S. and Iran were ongoing, Trump later said no discussions were taking place or scheduled for the future.

The announcement also comes as the United Arab Emirates announced this week that it would suspend all financial and commercial ties with Tehran.