Iranian forces say they shot down a US “spy drone” before dawn on Thursday, sending a new jolt of anxiety through the Persian Gulf amid the unraveling of a 2015 nuclear pact.

“Iran just made a very big mistake,” US President Donald Trump tweeted hours later, without elaborating.

The Iranian Revolutionary Guards on Thursday took responsibility for the drone’s downing, saying it was flying over Iran’s airspace.

“At the early hours of Thursday, the IRGC air force shot down an American spy drone, identified as RQ-4 Global Hawk that had violated Iranian airspace in the Kuh Mubarak region,” Iran’s state news agency reported, referring to a coastal point just outside the Strait of Hormuz in the Gulf of Oman.

The RQ-4 Global Hawk is a “high-altitude, long-endurance unmanned aircraft system” which is operated by US Air Force reconnaissance squadrons based in California and North Dakota, according to Military.com.

The US said the incident happened in international airspace over the adjacent Strait of Hormuz – the narrow passage between the Persian Gulf and the Gulf of Oman through which 20% of the world’s oil passes.

“Iranian reports that the aircraft was over Iran are false,” US Central Command spokesman Bill Urban said, calling the incident an “unprovoked attack on a US surveillance asset”.

The fresh confrontation comes a week after two tankers laden with petroleum products were attacked and their crews forced to evacuate in the Gulf of Oman. US Central Command released a video purporting to show an Iranian patrol ship removing a limpet mine from the hull of one of the tankers – ostensibly to conceal evidence of Tehran’s involvement.

The US blamed Iran for the attacks, a charge Tehran vehemently denied, and said it would send 1,000 new American troops to the region.

It also comes against the backdrop of increased militarization in this critical oil-exporting region and growing concern in the US Congress over a potential war with Iran.

Brian Hook, the US Special Representative for Iran, testifies before a House Foreign Affairs Subcommittee on the Middle East, North Africa, and International Terrorism hearing at the Capitol in Washington on June 19, 2019. Photo: AFP/Andrew Caballero-Reynolds

The hawkish US National Security Advisor John Bolton announced the deployment of an aircraft carrier and strike group to the Middle East in May.

In Yemen, where the US is providing bombs and logistics for a Saudi-led military campaign, the Iran-allied Houthis have steadily improved their drone and missile capabilities – most recently claiming an attack on a power station in neighboring Saudi Arabia.

Iraq also risks becoming a theater for a confrontation between the US and Iran – on Wednesday, an unclaimed rocket attack in the southern oil hub of Basra forced Exxon Mobil to evacuate workers.

Maximum pressure’s fruits

Iran’s firm response to US surveillance over or near its airspace comes amid a high stakes gambit with world powers over its integration in the world economy.

Iran’s atomic energy agency says the country is set to overstep enriched uranium limits set by the Iran nuclear deal – the Joint Comprehensive Plan of Action – on June 27, only one week away.

The Trump administration, which broke the United States’ commitment to the treaty in May last year, has nevertheless warned Iran against stepping away from its obligations.

Iran argues that the benefits of the deal have gone unfulfilled after the US imposed crippling global sanctions, namely against its petroleum exports. The European signatories did come up with a timid trade tool, INSTEX, at the start of the year, but it is far from the investment and economic engagement the Rouhani government was seeking.

Major European companies like Total had long since pulled out of Iran and shifted their focus to rival Saudi Arabia, whose market has been blessed by the Trump administration.

With the US working daily to bring Iran’s oil and gas exports to zero, with tightening room for waivers for allies like Iraq, Iran has been placed in a desperate situation.

If the Islamic Republic is choked off from exporting its own oil, then the idea of closing the Strait of Hormuz to Arab oil exports becomes increasingly logical – if a last resort.

The tanker attacks carried out a week ago were likely designed to highlight the potential fallout from the Trump administration’s “maximum pressure” campaign against Iran – namely to the Gulf princes who stand to lose the most.