International airlines have started to alter course around Iranian airspace following the shooting down of a US military drone in the Gulf.

British Airways, Qantas, Lufthansa and KLM were among the carriers that said they were choosing to reroute flights, after the US Federal Aviation Administration issued a warning and blocked US-registered aircraft from flying over Iranian waters in the strait of Hormuz and the Gulf of Oman.

The FAA’s emergency “notice to airmen” – notam – warned of a “potential for miscalculation or misidentification” in the area, a heavily used corridor for global flights, including from the US and Europe through the Middle East to India and Australia.

On Thursday, an Iranian surface-to-air missile shot down a US Global Hawk drone, a $130m (£102m) unmanned aircraft the size of a commercial passenger jet. The FAA said there were passenger planes in the air 45 miles away when the strike occurred.

The US carrier United Airlines has suspended flights between Newark airport near New York and Mumbai due to safety fears.

Timeline Recent tensions in the Gulf Show The UAE says four commercial ships off its eastern coast 'were subjected to sabotage operations'. Yemen's Houthi rebels launch a drone attack on Saudi Arabia, striking a major oil pipeline and taking it out of service. Saudi Arabia subsequently blames Iran for the attack. A rocket lands near the US embassy in the Iraqi capital, Baghdad, without harming anyone. It's not clear who is behind the attack, but after the initial reports, Donald Trump tweets: 'If Iran wants to fight, that will be the official end of Iran. Never threaten the United States again!' Saudi Arabia says 26 people were wounded in an attack by Yemen's Houthi rebels on an airport in the kingdom's south-western town of Abha. Two oil tankers near the strategic strait of Hormuz were reportedly attacked in an assault that left one ablaze and adrift. 44 sailors were evacuated from both vessels and the US navy assisted. Iran’s Revolutionary Guards say they have shot down what they called a US 'spy' drone they claim was flying in in the country’s airspace. The US military confirm one of its drones has been taken down, but say it was in international airspace. Donald Trump reportedly gives approval for the US military to launch strikes on Iran in retaliation for the loss of the drone, before pulling back at the last minute. The Iranian and US presidents trade insults, with Hassan Rouhani suggesting that Donald Trump suffered from a “mental disorder” and Trump once more threatening Iran with “obliteration”. Iran summons UK ambassador over an incident off Gibraltar as Royal Marines seize a tanker, Grace 1, the UK suspects of carrying oil to Syria. The International Atomic Energy Agency, the body tasked with verifying Iranian compliance with the terms of the nuclear deal, verifies that Tehran has breached the agreed 3.67% limit for enriched uranium. The UK government says three Iranian boats were warned off by the frigate HMS Montrose after Iranian boats 'attempted to impede' a British oil tanker in strait of Hormuz. Tehran denies involvement. In a major escalation, Iran seizes the Stena Impero, a British-flagged tanker, off its coast. Iranian officials later make it clear that the capture was in retaliation for the capture of the Iranian supertanker Grace 1 earlier in July. Despite US attempts in the courts to prevent it, Gibraltar says it will free oil tanker at centre of the Iran row. Iran gives assurances the oil is not destined for Syria, where selling it would breach international sanctions against Britain accuses Iran of breaching those assurances after Tehran acknowledged the oil had been sold, and the reflagged tanker Adrian Darya 1, previously known as Grace 1, had reached its final destination after the ship was photographed off the coast of Syria.

BA said it was adhering to the FAA guidance to avoid the area but flights continued to operate as normal, using alternative routes. “Our safety and security team are constantly liaising with authorities around the world as part of their comprehensive risk assessment into every route we operate,” a spokeswoman said.

Qantas said it would reroute its Australia-London flights, while the German carrier Lufthansa and KLM of the Netherlands said they would avoid the strait – although Lufthansa will continue flights to Tehran.

Dutch nationals made up the majority of the 298 people killed when Malaysia Airlines flight MH17 was shot down over Ukraine in 2014.

Opsgroup, which provides intelligence to airlines, said “the threat of a civil aircraft shootdown in southern Iran is real”. It said the Iranian weapon that attacked the US drone was comparable to the Russian Buk system that shot down the Malaysian plane.

According to Associated Press, the FAA notam is the second this year to suggest Iranian weapons could fire on an airliner in error, a possibility Tehran has dismissed, although in 1988, a US navy warship said it mistook an Iranian passenger plane in the Gulf for a fighter, shooting it down and killing 290 people.

Qatar Airways had yet to respond to requests for comment, but flights appeared to be continuing to fly through Iranian airspace, including the strait of Hormuz. The airline, which codeshares with BA on many flights, has been barred from the skies of Gulf neighbours including Saudi Arabia since 2017, forcing it north on many flights.

Emirates, based in Dubai, has the closest major hub to the affected area. The airline said it was taking precautionary measures including rerouting all flights away from areas of possible conflict, but the disruption had “minimally affected” the timings of flights.

“We are carefully monitoring the ongoing developments and are in close contact with the relevant government authorities with regards to our flight operations,” a spokesman said.

Etihad, based in Abu Dhabi, said it had contingency plans in place. The carrier said it would decide if any action was required after “carefully evaluating” the FAA directive.

Diversions could mean further costs for Gulf long-haul airlines, the operations of which have been subject to years of intense lobbying by US carriers over perceived unfair competition. The Gulf airlines have been affected by Donald Trump’s travel bans targeting predominantly Muslim countries, and prohibitions on laptops in cabins.