Library Picture of US Troops Afghanistan entering black hawk helicopter.
The Pentagon has said that due to "emerging threats" troops shall be deployed to Saudi Arabia "to strengthen regional security and stability".
The move has been approved by the King of Saudi Arabia, King Salman.
US troops have not been in Saudia Arabia since 2003, when they withdrew from the area at the end of the war with Iraq.
Reports suggest that the US is deploying Patriot air defence missile batteries, manned by 500 soldiers to Prince Sultan Base in Saudi Arabia.
Plus, a squadron of F-22 stealth fighters to the base.
The RQ-4 Global Hawk, believed to be the drone shot down, is a high altitude, long-endurance craft (Picture: US Air Force).
Tensions between the US and Iran have been rising since the US withdrew from the 2015 nuclear deal, which led to the them then tightening sanctions imposed on Iran's oil sector.
Last month, an American military drone worth $100 million (£78 million) was downed by Tehran, with Iran's president Hassan Rouhani claiming it had violated their airspace.
The US has also called on Iran to release a Panamanian-flagged tanker and 12 of its crew, which was seized by Revolutionary Guards on Sunday during a naval patrol due to the belief the vessel was smuggling fuel.
Then on Thursday President Donald Trump said a US warship has "destroyed" an Iranian drone in the Strait of Hormuz.
He claimed it was the latest "hostile" action by Iran.
The US has also blamed Iran for two separate attacks on oil tankers in the Gulf of Oman in May and June.
Tehran has denied this allegation.