Democratic leaders of the United States have insisted on congressional approval before the launch of any military operation against Iran.
Democrats fear the US could "bumble" into a war with Iran over the shooting down of an unmanned American surveillance drone.
The US Federal Aviation Administration has banned American aircraft from flying over parts of Iranian controlled airspace.
President Donald Trump has called it a "very big mistake" by Iran but Tehran said it shot down the unmanned aircraft in its airspace.
Al Jazeera's Mike Hanna has more from Washington, DC.