20 June, 2017
Areas of northern Syria west of the Euphrates were controlled by IS before Syrian government forces captured a lot of them in recent months.
"Right now what we have is a policy of ambiguity", said Ilan Goldenberg, director of the Middle East security program at the Center for a New American Security.
Russia, a key ally of Syrian President Bashar Assad, called on the US military to provide a full accounting as to why it chose to shoot down the Syrian Su-22 bomber. Back in April, Russia gave the US the cold shoulder after Americans fired 59 missiles on a Syrian air base after a chemical weapons attack. Meanwhile, Iran's missile attack, which it said was in response to the Islamic State's recent raid on the parliament building in Tehran, was a bold assertion of its willingness to escalate militarily in Syria and maybe elsewhere in the region. In April, Russia briefly suspended cooperation after the US military fired 59 missiles at a Syrian air base following a chemical weapons attack that Washington blamed on the Assad government.
Moscow said it would treat US -led coalition aircraft flying west of the River Euphrates in Syria as potential targets and track them with missile systems and military aircraft.
Ozerov insisted that Russia will be tracking the coalition's jets, not shooting them down, but he added that "a threat for those jets may appear only if they take action that pose a threat to Russian aircraft".
The line has been a lifesaving - albeit imperfect - tool since it was set up soon after Russian Federation entered Syria's civil war in late 2015 to prop up President Bashar al-Assad.
Adding to the tension, Iran launched missiles at Islamic State targets in eastern Syria on Sunday, a strike seen as a projection of military power into part of Syria identified as a top priority by Damascus and its allies. Previously, it has been providing crucial support to Assad's forces. The muscle-flexing comes amid the worsening of a long-running feud between Shiite powerhouse Iran and Saudi Arabia, with supports Syrian rebels and has led recent efforts to isolate the Gulf nation of Qatar.
Some Trump appointees saw Iran's missile strike as an illustration of Tehran's regional ambitions, which they have argued make it an existential enemy, according to the three USA officials. "Iran's missile capability protects its citizens in lawful self-defense & advances common global fight to eradicate (IS) & extremist terror", he wrote. No need to remember your password or log in, just click.
The U.S. launched 59 missiles at the Shayrat air base in early April in response to a chemical attack that was blamed on the Syrian government and Assad.
Other Iranian officials were more blunt in their assessment of the attack.
On multiple occasions, the USA has used the line to warn pro-Syrian regime forces to stay at arm's length from US and partner forces operating near Raqqa and Tabqa cities, as well as those operating near a USA training facility for anti-ISIS forces in Tanf, on the border with Iraq in southeastern Syria.
Bolstered by coalition air-power, Kurdish forces in Syria have entered the second week of fighting to seize the city of Raqqa, where almost 2,000 ISIS fighters are battling to maintain control of their de facto capital in a bloody street-by-street battle.
Government forces have also been attacking IS in northern, central and southern Syria, seizing 25,000 square kilometers (9,600 square miles) and reaching the Iraqi border for the first time in years.
The SDF however accused the Syrian government on Monday of attacking its positions using planes, artillery and tanks.
SDF spokesman Talal Sillo said the government aims to thwart the SDF offensive to capture the city of Raqqa.
However, the hotline in recent weeks has become more important than ever to aid in decongesting the tight airspace over Raqqa, and has grown to include deconflicting military ground maneuvers between Syrian regime forces and its proxy elements, and the USA government's Syrian allies in and around the Euphrates river valley.