The Iranian official said the aircraft "definitely belonged to a foreign country", but would not say which. "Its wreckage has been recovered and is being investigated", the governor of Khuzestan, Gholamreza Shariati, said, according to the official IRNA news agency.
It later said the drone could have been an Iranian model downed during nighttime exercises to test missile systems. Iran has claimed to have shot down drones before, only for further news on the incidents not to be made public.More news: Helen Mirren Responds to Keanu Reeves GF Comparisons
US Central Command, which has responsibility for Washington's military operations in the Middle East, said on Twitter on Friday "alleged reports of a US drone being shot down are incorrect". Israel, another party that could fly a surveillance UAV inside Iranian airspace, declined to comment on the incident.
The unmanned aircraft was downed with a domestically manufactured Mersad surface-to-air missile, said Tasnim news agency which is close to the ultra-conservatives. The short video showed a missile being launched from the ground followed by an explosion in the sky. Tehran said the drone "violated" its territorial airspace, while the USA called the missile fire "an unprovoked attack" in global airspace over the narrow mouth of the Persian Gulf.
In June, US president Donald Trump authorised a strike on Iran after an American drone was shot down, only to call off the attack at the last minute amid fears that it would lead to excessive civilian casualties.More news: Weird text messages overnight? Sprint says update caused message confusion
In June, Iran shot down an unmanned US surveillance drone, which the elite Revolutionary Guards said was flying over southern Iran.
Regional tensions remain high over Tehran's collapsing nuclear deal with world powers, which the USA unilaterally withdrew from over a year ago.
Israel says it has carried out hundreds of air strikes in neighboring Syria, some of them against Iranian targets, to prevent Tehran from establishing a presence there.More news: When will the Modern Warfare seasonal Battle Pass be released?
Yemen's Iran-backed Houthi rebels claimed responsibility, but the United States says the attacks involved cruise missiles from Iran and amounted to "an act of war".