A Boeing Co. 737-838 aircraft operated by Qantas Airways Ltd. approaches to land at Sydney Airport in Sydney, Australia, on Thursday, Feb. 21, 2019.

Some global airlines are redirecting flights to avoid Iran-controlled airspace over the Gulf of Oman and the Strait of Hormuz, citing safety concerns amid intensifying fears of a military confrontation in the Middle East.

A flurry of airlines, including British Airways, Qantas, Lufthansa, Singapore Airlines and Air-France KLM's Dutch subsidiary KLM, announced they would avoid parts of Iranian airspace Friday morning.

It comes after a day of escalating tensions between the U.S. and Iran. President Donald Trump reportedly approved military strikes against the Islamic Republic late Thursday, before abruptly reversing his decision after intense discussions with top national security officials at the White House.

Earlier on Thursday, U.S. officials said an Iranian missile had shot down an unmanned American surveillance drone over the Strait of Hormuz, the world's busiest transit lane for seaborne oil shipments.

Increased geopolitical tension prompted the U.S. Federal Aviation Administration (FAA) to issue an emergency order to its carriers. The FAA said U.S. operators would be prohibited from flying in an overwater area of Iran-controlled airspace over the Strait of Hormuz and Gulf of Oman until further notice.

The downing of the unarmed Global Hawk aircraft, which can fly at up to 60,000 ft (18,300 m), was the latest of a series of incidents in the Gulf region, a critical artery for global oil supplies, that included explosive strikes on six oil tankers.

In a separate advisory to operators, the FAA said according to flight tracking applications, the nearest civil aircraft was operating within around 45 nautical miles of a U.S. Global Hawk drone when it was shot down by an Iranian surface-to-air missile this week.