Iran's Revolutionary Guard announced Thursday that it had shot down a U.S. drone over its territory, but a U.S. official reportedly says the targeted unmanned aircraft was operating in international airspace.

IRNA quoted Iran's Islamic Revolutionary Guard Corps Thursday as saying it downed an RQ-4 Global Hawk surveillance drone after it entered Iranian airspace around Kouhmobarak district in country's south near the Gulf of Oman. The IRGC's media arm, Sepah News, described the craft as a "spy" drone.

Initially, U.S. Navy Capt. Bill Urban, a spokesman for the U.S. Central Command, was quoted by The Associated Press as saying: "There was no drone over Iranian territory." He told Reuters that "No U.S. aircraft were operating in Iranian airspace today."

Later however, Reuters and The Associated Press quoted U.S. officials speaking on condition of anonymity, who acknowledged that an American drone was shot down by a surface-to-air missile, but that the incident occurred in international airspace over the Strait of Hormuz.

It was not immediately clear whether the news agencies were quoting the same individual or two separate officials.

Earlier this week, the Pentagon said Iran had attempted to shoot down a U.S. drone. It also acknowledged the successful shooting down of an MQ-9 Reaper drone on June 6 by Yemen's Houthi forces, which are allied to Iran. The U.S. said Iran helped the Houthis bring down the pilotless aircraft.

The U.S. did not immediately confirm what type of drone was involved in Thursday's incident. Military.com describes the Global Hawk as an unarmed high-altitude, long-endurance UAV for intelligence, surveillance and reconnaissance. The vehicle reportedly has a top speed of nearly 355 mph and a range of 10,000 miles.

The area where Iran says the drone went down is near where the U.S. claims Iran attacked two oil tankers last week. Iran has repeatedly denied the attack.

The alleged shootdown comes at a time of heightened tensions between the U.S. and Iran, with not only the alleged attacks on the tankers, but with Iran threatening to step up its nuclear activities.

Last year, the Trump administration reimposed sanctions on Tehran after abruptly withdrawing from a 2015 multinational agreement to limit Iran's nuclear program.

Despite Washington's withdrawal, the Joint Comprehensive Plan of Action, or JCPOA, technically remains in force with the other signatories — besides Iran, the other four permanent members of the U.N. Security Council and the European Union.

However, earlier this week, a spokesman for Iran's atomic energy agency warned that Tehran would surpass limits on its uranium stockpile under the deal and said it was prepared to increase its enrichment to a level just one step short of weapons-grade, which also violates the terms of the agreement.

Also, Houthi rebels in Yemen on Wednesday said they hit a Saudi power station with a cruise missile. White House spokesman Sarah Sanders said President Trump had been "briefed on the reports of a missile strike in the Kingdom of Saudi Arabia."

"We are closely monitoring the situation and continuing to consult with our partners and allies," Sanders added.

Copyright 2019 NPR. To see more, visit https://www.npr.org.