Iran’s Islamic Revolution Guards Corps (IRGC) said it shot down the drone over Iranian airspace, near Kuhmobarak in the southern province of Hormozgan.
IRGC commander Maj-Gen Hossein Salami said the incident sent “a clear message to America”, state media said.
It comes at a time of escalating tension between the US and Iran.
On Monday, the US defence department said it was deploying 1,000 extra troops to the region in response to “hostile behaviour” by Iranian forces.
The US has accused Iran of attacking two oil tankers with mines last Thursday just outside the Strait of Hormuz, in the Gulf of Oman. Iran rejects the allegation.
Tensions were further fuelled on Monday when Iran said its stockpile of low-enriched uranium would next week exceed limits it agreed with world powers under a landmark nuclear deal in 2015.
Iran stepped up its production in response to tightening economic sanctions from the US, which unilaterally withdrew from the deal last year.
The IRGC said it shot down a US surveillance drone in the early hours of Thursday after it violated Iranian airspace, the official Irna news agency reported.
The drone was identified by the IRGC as…