Iran shot down a US drone and said it's 'ready for war' - but whether it had any right to rests on a murky technical distinction

Google Maps/Business Insider; US Navy/Northrop Grumman/Bob Brown/Handout via Reuters

Map showing the discrepancies between the US and Iranian accounts of where a drone was shot down. Inset: A US Navy MQ 4C Triton drone, which US officials said was shot down.

• Iran's paramilitary Revolutionary Guard shot down a US drone Thursday morning around the geopolitically important Strait of Hormuz.
• Iran says it took down the drone when it entered Iranian airspace. But the US said the the Navy drone was never in Iranian territory and was flying in international airspace.
• If the US drone was in international airspace, rather than Iran's, then the Guard had no right to shoot it down.
• The commander of the Guard said it shot down the drone to send "a clear message" that "we are ready for war."
• The White House has also signaled willingness to attack Iran, which Secretary of State Mike Pompeo argues could be done without asking Congress.
• Visit Business Insider's homepage for more stories.

Iran's Revolutionary Guard said on Thursday morning it shot down a US Navy drone, to make clear its position that "we are ready for war."

However, Iran and the US sharply differ over whether Iran had any right to take action, based on a technical argument over whose airspace the aircraft was in.

The Guard's website, Sepah News, said it shot down a "spy" drone when it flew over the southern Hormozgan province, located by the Gulf, Reuters reported.

IRNA, Iran's state news agency, also said the Guard struck the drone when it entered Iranian airspace, according to the Associated Press (AP).

REUTERS/Stringer/File Photo

Members of the Iranian Revolutionary Guard at a parade in Tehran in September 2011.

Gen. Hossein Salami, the commander of Revolutionary Guard, said in a televised speech on Thursday that the drone-shooting sends "a clear message" to the US not to attack Iran.

He said that Iran does "not have any intention for war with any country, but we are ready for war," according to the AP.

Iran's foreign ministry has also accused the US of "illegal trespassing and invading of the country's skies."

"Invaders will bear full responsibility," a statement said, according to the AP.

The US has, however, denied flying any aircraft over Iranian airspace.

It said instead that a US Navy drone was shot down in international airspace in the nearby Strait of Hormuz, Reuters reported, citing an unnamed US official.

Google Maps/Business Insider

Map showing the southern Hormozgan province in Iran, where Iran says a US drone had entered when it got shot down; and international airspace over the Strait of Hormuz, which US officials say a Navy drone was shot down.

Capt. Bill Urban, a spokesman for the US military's Central Command, also told the AP earlier on Thursday: "There was no drone over Iranian territory."

If the US drone was flying in international airspace, Iran had no right to attack it.

Business Insider has contacted the Department of Defense for comment on the discrepancies and the Guard commander's message.

Tensions between the US and Iran ratcheted up in recent weeks after the US accused Iran of attacking an oil tanker in the Gulf of Oman two weeks ago.

US Navy/Handout via Reuters

The MQ-4C Triton at Naval Air Station Patuxent River in September 2014. The US said this drone was shot down over the Strait of Hormuz, according to Reuters.

Iran last week retaliated by saying it will exceed the limits on its enriched uranium stockpile as agreed in the 2015 nuclear deal signed under former President Barack Obama's administration, from which President Donald Trump withdrew last year.

Read more: Here's what's in the landmark nuclear deal that Iran is starting to walk away from, amid tensions with Trump

The hawkish Revolutionary Guard is a powerful force within Iran's ruling class, and tends to favor an aggressive foreign policy.

Michael Gruber/Getty Images; Olivier Douliery-Pool/Getty Images; Samantha Lee/Business Insider

President Donald Trump's administration has signaled willingness to go to war with Iran in recent days.

Secretary of State Mike Pompeo has made the case that the US might be able to attack Iran under a law originally passed to allow then-President George W. Bush to punish those deemed responsible for the September 11, 2001, terror attacks.

Both Republican and Democratic lawmakers are resisting the White House's use of that act to justify action against Iran.