The five-second clip, published Friday by the Islamic Republic of Iran Army, shows an unidentified surface-to-air missile system firing into the night sky.
Iran shot down an unidentified drone that "infiltrated" near Bandar-e Mahshahr port on the Gulf coast Friday, Iranian media reported, after the downing of a U.S. drone almost triggered air strikes earlier this year.
The brigadier general did not specify from which country the device launched or identify its national origin, but U.S. Central Command, which lost a state-of-the-art spy drone to Iranian air defenses in June, tweeted: "Alleged reports of a U.S. drone being shot down are incorrect".
Both countries have repeatedly challenged one another's claims, with the US denying its device violated Iranian airspace, and Tehran denying its drone was hit at all in July.
Iran's air defence force hit the "unknown" drone early on Friday morning at the port city of Mahshahr in the country's southwest, IRNA reported.
Gholamreza Shariati, the governor of the Khuzestan province where Mahshahr is located, said a wreck of the drone was recovered from the marshlands in the suburbs of the city.
Iran has denied involvement and warned the U.S. any attack will spark an "all-out war" with immediate retaliation from Tehran.
A US Defense official told the MailOnline: 'There are no reports of a USA drone being shot down'.
In June, Iran shot down an unmanned U.S. surveillance drone, which the elite Islamic Revolutionary Guard Corps (IRGC) said was flying over southern Iran - a move that brought the region to the brink of war.
The incident comes amid soaring tensions between Tehran and Washington.
Neither news agency gave any further details of the incident which comes amid soaring tensions between Tehran and Washington since President Donald Trump unilaterally abandoned a landmark 2015 nuclear deal a year ago and reimposed crippling sanctions.
Israeli Prime Minister Benjamin Netanyahu hinted in August at possible Israeli involvement in attacks on Iranian-backed militia positions in Iraq.
"Alleged reports of a US drone being shot down are incorrect".
There was no immediate comment from the United States.