WASHINGTON (AP) -- The skies over Syria are increasingly crowded — and increasingly dangerous. The air forces of multiple countries are on the attack, often at cross purposes in Syria's civil war, sometimes without coordination. And now, it seems, they are at risk of unintended conflict.
The latest entry in the air war is Russia. It says it is bombing the Islamic State in line with U.S. priorities, but the U.S. says Russia is mainly striking anti-government rebels in support of its ally, President Bashar Assad. The Russians, who are not coordinating with the Americans, reportedly also have hit at least one U.S.-supported rebel group.
That opens the possibility, however unlikely, of the Americans and Russians coming to blows.
For its part, Turkey in late August began airstrikes in Syria as part of the U.S.-led anti-Islamic State coalition. Turkish warplanes are fully integrated into the coalition attack plan, as are those of Australia, which began flying strike missions over Syria in September. France also began bombing in September.
And Syria's air force is also bombing targets within its borders, hitting both Islamic State and anti-government rebels, all of whom Assad has labeled "terrorists" with a broad brush.
U.S. and Russian defense officials held a one-hour video teleconference last week on ways to "de-conflict" Syrian airspace, or prevent unintended air incidents, including collisions. No agreement was reached. More talks are expected, although a senior defense official said Monday there had been no further word from Moscow, raising doubt about Russian intentions. The official was not authorized to discuss the matter and thus spoke on condition of anonymity.
The introduction of the Russian planes in the crowded skies over Syria endangers not only air forces and military pilots, but non-combatants on the ground, as well.
Defense Secretary Ash Carter has expressed worry about the possibility of "inadvertent incidents and lack of communication" with Russian air crews, although so far the Russians have flown mainly in western Syria, relatively far from U.S. and coalition flights in the country's north and east.
The picture darkened further on Monday as Turkey's prime minister vowed to protect the nation's borders after a Russian fighter jet entered Turkish airspace from Syria over the weekend. The incursion, which Russia said was an accident, prompted Turkey to scramble jets to intercept the Russian plane. Turkey also lodged a diplomatic protest.
The secretary general of NATO rejected Moscow's claim that its military incursion into alliance airspace over Turkey wasn't intentional or important, saying there were two separate incidents and "the violation lasted for a long time."
Jens Stoltenberg told a news conference in Brussels on Tuesday that the reported incidents were "very serious." Stoltenberg added, "It doesn't look like an accident, and we've seen two of them over the weekend."
The violation is more than a Turkey-Russia spat because Turkey is a member of the NATO alliance, whose defense leaders meet later this week in Brussels. Russia is not a NATO member. Carter said he expects the matter to be on the NATO agenda, and he repeated his strong criticism of the Russian military involvement in Syria, calling it "doomed to fail" and "way off track."
"What we're seeing now is a lot of different countries and coalitions operating in the skies over Syria," said Stephane Dujarric, spokesman for U.N. Secretary-General Ban Ki-moon. "I think it creates a situation that is fraught with danger and very delicate, as we'd seen in the issue of the violation of the airspace with Turkey ... This should really refocus people's attention on finding a political solution."
Russian officials say more than 50 warplanes and helicopters are taking part in the open-ended air operations, including Su-24M, Su-25 and Su-34 jets. They are flying 20-25 missions a day in Syria, compared to an average of about eight per day by the U.S.-led coalition.
In addition to its air campaign, Russia has brought ground combat weaponry into western Syria, according to U.S. officials. This includes a small number of artillery pieces and multiple-launch rocket systems moved in recent days to the vicinity of Hama, southeast of the coastal air base where Russia has staged most of its aircraft, a U.S. defense official said.
The U.S. has no ground troops in Syria but is training what it considers to be moderate Syrian rebels at bases in Jordan and Turkey.
The U.S. has been concerned that Turkey's focus in Syria may not be entirely aligned with Washington's, given the Turks' worry about Syrian Kurdish forces near its border. The U.S. worked closely with the Kurds to oust Islamic State forces from the northern city of Kobani, whereas the Turks have shelled, but apparently not conducted airstrikes against, those same Syrian Kurds.
In addition to Turkey, France and Australia, the U.S. coalition partners participating in the Syria air campaign include Jordan, Saudi Arabia and Canada. Turkey, however, carried out only one airstrike against IS before turning its attention to bombing Kurdish positions in Syria and Iraq.The U.S. is experienced at coalition warfare, particularly in the Middle East, where it has a highly sophisticated air operations center at al-Udeid air base in Qatar that works like a military air traffic control center, making sure all the flights are coordinated and targets are struck in line with common objectives.
But Syria is an unusually complicated case. Assad has his own air force as well as air defenses capable of threatening U.S. or other coalition aircraft, for one thing. So far he has not done so, but the situation is growing more complex as Russia get further involved militarily.
Thus far, U.S. military officials have played down the possibility of air accidents in Syria.
"While there's always the potential for miscalculation and for accidents, it's important to remember that there is a lot of square miles in Syria," Col. Steve Warren, spokesman for the U.S. military headquarters in Baghdad that is managing the air campaign in Iraq and Syria, said last week. "Most of these strikes are two or four aircraft participating. They fly in, they strike, they depart."