The US Federal Aviation Administration (FAA) has barred all American airlines from flying over Syria, citing fears that Islamists there have obtained anti-aircraft weapons that could endanger civilian planes.
The FAA on Monday ordered airlines based in the United States to stop flying over Syria, citing a "serious potential threat" to civilian planes.
The agency said the move was taken after an "updated assessment of risk" and a lack of airlines wishing to fly in the airspace. The new rule requires operators to contact the FAA before operating in the airspace.
"The ongoing armed conflict and volatile security environment in Syria poses a serious potential threat to civil aviation," the agency said in a statement.
Syria is in the midst of a civil war in which 170,000 people have died since 2011.
The FAA has warned that extremist groups in the country are known to be equipped with anti-aircraft weapons.
On Tuesday, Swiss-based research group Small Arms Survey said it expected "several hundred" anti-aircraft missile systems were in the hands of Syrian opposition militias, including Islamic fundamentalist groups.
Mostly Russian and Chinese in origin, the weapons had been seized from government forces or smuggled in from nations sympathetic with the insurgents, said the Swiss group, which monitors the global flow of weapons.
The weapons are known as "man-portable air defense systems," or MANPADS, which were dangerous to planes flying at low altitudes or landing and taking off at airports.
The ban imposed by the US aviation regulator applies to all US-registered planes, commercial operators and FAA-licensed pilots. It makes an exception for flights operated with US government permission and US-registered aircraft operated by foreign carriers.
The FAA this month also restricted US airlines and commercial operators from flying over Iraq while the US Air Force launches air strikes against Islamic State insurgents.
uhe/cjc (Reuters, AP, AFP)