Idlib is one of the last main strongholds of rebels opposed to President Bashar al-Assad, who have been driven from most of their bastions in Syria since Russian Federation joined the war on the side of Assad's government in 2015.
The Syrian Foreign Ministry also doubled down, calling the USA strikes "new aggression that poses a war crime and a crime against humanity".
Idlib is the largest chunk of Syrian territory held by insurgent factions opposed to President Bashar al-Assad's government.
Quoting an unnamed USA official, Reuters news agency said that the coalition was responding to an attack against the US-backed Syrian Democratic Forces (SDF) in Deir Az Zor.
While U.N. officials say hundreds of thousands of people have been killed in the conflict, regime officials say the death toll is closer to 10,000.
Meanwhile, the US-led coalition fighting the Islamic State in Iraq and Syria (ISIS) on Thursday reported that it had struck pro-Assad forces following "an unprovoked attack", a rare instance of the U.S. attacking the regime, which is supported by Moscow.More news: Turkish Military Helicopter Shot Down In Syria
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Turkey views the presence of Syrian Kurdish militants, known as the YPG, as a threat to its security, saying the group is an extension of the outlawed Kurdistan Workers' Party (PKK).
Smoke plumes rising following a reported regime air strike in the rebel-held town of Arbin, in the besieged Eastern Ghouta region on the outskirts of the capital Damascus, February 7, 2018.
Another 812 civilians were injured, it said.
Additionally, since the USA and its coalition allies launched Operation Inherent Resolve in 2014, they have carried out thousands of airstrikes against Islamic State targets.
"Eastern Ghouta is experiencing a Middle Ages-style siege".
The state-run Anadolu news agency said the raids began at midnight.
They discussed the humanitarian situation in Eastern Ghouta, just outside Damascus, where dozens have been killed in aerial strikes in the past few days.