Iran's elite Revolutionary Guards have shot down a US "spy" drone in the southern province of Hormozgan, the Guards' news website Sepah News said on Thursday.
State news agency IRNA carried the same report, identifying the drone as an "RQ-4 Global Hawk'.
"It was shot down when it entered Iran's airspace near the Kouhmobarak district in the south," the Guards' website added.
The RQ-4 Global Hawk unmanned aircraft system (UAS) can fly at high altitudes for more than 30 hours, gathering near-real-time, high-resolution imagery of large areas of land in all types of weather, maker Northrop Grumman says on its website.
"No US aircraft were operating in Iranian airspace today," Navy Captain Bill Urban, a spokesman for the US military's Central Command, said shortly before midnight on Wednesday.
Urban declined further comment. The US military has in recent days confirmed an attempt by Iran to shoot down a US drone last week as well as a successful shoot down of one on June 6 by Iran-aligned Houthi forces in Yemen.
Tension between Iran and the United States has spiked since last year when President Donald Trump exited a 2015 nuclear deal between Tehran and major powers and reimposed sanctions on the country.
Concerns about a military confrontation between Iran and the United States have mounted since attacks on two oil tankers in the Gulf of Oman last week and four tankers off the United Arab Emirates on May 12, both near the Strait of Hormuz, a major conduit for global oil supplies.
The United States and its regional ally Saudi Arabia have blamed Iran for the incidents. Iran has denied responsibility.
To counter Iran's threats, the US military has sent forces, including aircraft carriers, B-52 bombers and troops to the Middle East. However, Trump said he does not seek war with Iran.
Iran said last week that it was responsible for the security of the Strait of Hormuz, calling on American forces to exit the Gulf.
In protest at Trump's "maximum pressure", in May Tehran said it would start enriching uranium at a higher level unless other European signatories to the deal protected its economy from the US sanctions within 60 days.
