Major airlines from around the world on Friday began re-routing their flights to avoid areas around the Strait of Hormuz following Iran’s shooting down of a US military surveillance drone there, as America warned commercial airliners could be mistakenly attacked.

The Federal Aviation Administration warned of a “potential for miscalculation or misidentification” in the region after an Iranian surface-to-air missile on Thursday brought down a US Navy

RQ-4A Global Hawk, an unmanned aircraft with a wingspan larger than a Boeing 737 jetliner and with a pricetag of $100 million.

The US said it made plans for limited strikes on Iran in response, but then called them off.

Australia’s Qantas, British Airways, Dutch carrier KLM, Emirates, Germany’s Lufthansa, Malaysia Airlines and Singapore Airlines said soon afterwards that they will avoid the region as well.

The FAA previously warned of a risk in the region, but Friday’s warning threw into stark relief a danger that both the agency and analysts say is real after the shooting down of a Malaysian Airlines flight over Ukraine in 2014.

That could further imperil the bottom lines of Gulf long-haul carriers, which already have faced challenges under the Trump administration.

“The threat of a civil aircraft shootdown in southern Iran is real,” warned OPSGROUP, a company that provides guidance to global airlines.

The FAA made a similar warning in May to commercial airliners of the possibility of Iranian anti-aircraft gunners mistaking them for military aircraft, something dismissed by Tehran some 30 years after the US Navy shot down an Iranian passenger jet.

Iran had no immediate reaction to the US announcement.

The FAA said its warning would affect the area of the Tehran Flight Information Region without elaborating.

The FAA’s operations centre referred questions to its press office, which did not immediately respond to queries from The Associated Press.

However, that likely only extends some 12 miles off the Iranian coast, aviation experts said. There are “heightened military activities and increased political tensions in the region, which present an inadvertent risk to US civil aviation operations and potential for miscalculation or misidentification,” the FAA said. “The risk to US civil aviation is demonstrated by the Iranian surface-to-air missile shoot-down of a US unmanned aircraft system on 19 June 2019 while it was operating in the vicinity of civil air routes above the Gulf of Oman.”

Qantas said it would re-route its London flights to avoid the Strait of Hormuz and Gulf of Oman. British Airways, KLM, Malaysia Airlines and Singapore Airlines said their flights would avoid the strait. Lufthansa said it would avoid both the Strait of Hormuz and the Gulf of Oman, as well as nearby land.

However, it said it would continue its flights to Tehran.

The Persian Gulf is home to some of the world’s top long-haul carriers, who already have been battered by Trump’s travel bans targeting a group of predominantly Muslim countries, as well as an earlier ban on laptops in airplane cabins for West Asian carriers.

Etihad, the Abu Dhabi-based long-haul carrier, said it had “contingency plans” in place, without elaborating.

“We will decide what further action is required after carefully evaluating the FAA directive to US carriers,” the carrier told The Associated Press.

Emirates, the long-haul carrier in Dubai near the Strait of Hormuz, said in a statement to AP that it was “re-routing all flights away from areas of possible conflict”. Its sister airline, the low-cost carrier FlyDubai, said it “adjusted some of the existing flight paths in the region as a precautionary measure”.

Qatar Airways did not immediately respond to requests for comment.

Iran said the drone “violated” its territorial airspace, while the US called the missile fire “an unprovoked attack” in international airspace over the Strait of Hormuz, the narrow mouth of the Persian Gulf.

OPSGROUP said the Iranian weapons system that shot down the drone was comparable to the Russian Buk system used in the Malaysian Airlines shootdown in Ukraine.

“Any error in that system could cause it to find another target nearby — another reason not to be anywhere near this part of the Straits of Hormuz,” OPSGROUP said.

President Donald Trump initially tweeted that “Iran made a very big mistake!” He later appeared to play down the incident, telling reporters in the Oval Office that he had a feeling “a general or somebody” being “loose and stupid” made a mistake in shooting down the drone.