Iran’s Revolutionary Guards Corps reports that it has downed a U.S. drone, while U.S. sources have denied the news.

On Tuesday, the Iranian State Radio and Television Network announced that a U.S. drone that has been on reconnaissance and intelligence-gathering missions in the Persian Gulf region entered Iranian airspace and was immediately captured by Iranian air defence forces.

IRGC commander Ali Fadavi reported that the drone was a Scan Eagle, adding that such aircraft usually take off from large carriers.

The Associated Press reports that the U.S. Navy has said all its unmanned aircraft in the Persian Gulf region are “fully accounted for.”

A spokesman for the U.S. Navy’s 5th fleet in Bahrain was quoted as saying that the fleet has lost a number of drones to the gulf waters in the past year, but there are no records of one being lost recently.

If Iran’s account is confirmed, this would be the second time Iranian military forces have captured a U.S. drone. Last December, Iran downed another U.S. drone near its border with Afghanistan.

In November, Iranian forces shot at a U.S. drone, claiming it had entered their airspace. The U.S. denied the accusations, saying the drone was flying in international airspace.

Mohammad Khazai, Iran’s envoy to the United Nations, has written to UN Secretary General Ban Ki-moon to warn the U.S. against “illegal and provocative” operations in Iran’s air and water border regions. He claimed that U.S. navy aircraft have on several occasions entered Iranian airspace and flown over Iran’s border regions.