Donald Trump approved a US military strike against Iran in retaliation for the downing of a drone earlier in the day, but abruptly reversed course at the last moment.

It was the New York Times that first reported the meeting in the White House Situation Room below the Oval Office that included administration officials and congressional leaders.  Some actively debated the plan, other were merely debriefed.  The main proponents of the attack were Secretary of State Mike Pompeo, National Security Adviser John Bolton, and CIA Director Gina Haspell.  

The plan on the table was generally considered a major escalation of the tensions between the US and Iran, and could have caused numerous civilian casualties, perhaps in the hundreds.  The chosen targets were radar installations and missile batteries. 

The New York Times reported that  a senior administration official said that "the operation was underway in its early stages when it was called off", and that "planes were in the air and ships were in position, but no missiles had been fired when word came to stand down".

Iran shot down a US drone early Thursday, releasing GPS coordinates it says proves the drone flew into its sovereign territory.  The US maintains the drone was operating in international airspace.