Russia’s long-range missile strikes against targets in Syria have prompted aviation safety authorities to issue a safety alert to airlines flying in Iraq, Iran, and over the Caspian Sea amid growing concerns about the risk to commercial flying near conflict zones.

Russia this week said it fired cruise missiles from the Caspian Sea against Syrian targets—nearly 1,000 miles away—as Moscow steps up its support of Syrian President Bashar al-Assad. The U.S. and other Western countries have denounced the strikes. Russia denies U.S. assertions that some of the missiles fell short, landing in Iran.

The International Civil Aviation Organization, the United Nations’ air-safety arm, on Oct. 9 warned of “the possible existence of serious risks to the safety of international civil flights” flying in the wider airspace around Baghdad, Damascus and Tehran.

The European Aviation Safety Agency said it issued a safety information bulletin to airlines on Oct. 9 in response to the missile strikes. “Before reaching Syria, such missiles are necessarily crossing the airspace above Caspian Sea, Iran and Iraq, below flight routes which are used by commercial transport aeroplanes,” said the organization, which is based in Cologne, Germany.

Safety bulletins are issued to alert airlines about potential hazards to commercial flights and used by carriers to make flight plans. EASA said it had no specific recommendations on what actions airlines should take.

Fighting in Iraq has previously triggered such notices and led to restrictions on operating in some Iraqi airspace.

ICAO said some airlines have resorted to alternative routing during and after the missile firings. It also said such adjustments to flight plans could increase the density of jetliners on the alternative routes and affect overall airspace capacity.

Airline-safety authorities have become particularly attuned to the risk of flying near conflict zones after Malaysia Airlines Flight MH17 was downed on July 17, 2014, while cruising at 33,000 feet over eastern Ukraine on a flight from Amsterdam to Kuala Lumpur. All 298 people onboard the Boeing Co. 777 jetliner were killed.

Ukraine and the U.S. accuse pro-Russian separatist rebels of having shot down the plane with a sophisticated antiaircraft missile. Russia denies the claim. The Dutch Safety Board, which is leading the probe into the crash, is due to release its final report on the downing of the Malaysian jetliner on Tuesday.

Click for more from The Wall Street Journal.