Russia has increased its airstrike campaign on the northwestern Syrian province of Idlib in the past few days, which rights group warn could lead to a new humanitarian crisis in the war-torn country.
More than 100 Russian airstrikes have targeted Idlib and parts of the neighboring province of Hama in recent days, the Syrian Observatory for Human Rights told VOA.
The observatory, which has researchers across Syria, charged that Syrian government helicopters have also dropped barrel bombs on towns and villages across Idlib.
"The Russian escalation has a clear message to al-Nusra Front," said Rami Abdulrahman, director of the observatory, told VOA.
"This is also a message to everyone else, including the U.S., that when it comes to northwestern Syria, it's only Russia who calls the shots," Abdulrahman added.
Since late April, militants have launched several military operations against Syrian regime troops, killing scores of them, which prompted the recent Russian bombardment that has killed dozens of civilians, according to local media reports.
Russia has been backing the Syrian regime since 2015, helping government forces and allied militias recapture rebel-held cities such as Aleppo, Homs, Daraa and Damascus suburbs.
Idlib is under the control of a former al-Qaida affiliate called Hayat Tahrir al-Sham (HTS), which was formerly known as the al-Nusra Front. The Syrian province is the last stronghold of rebel forces battling the regime of Syrian President Bashar al-Assad.
Since the outbreak of Syria's civil war in 2011, the U.S. has twice carried out airstrikes against Syrian regime targets, punishing Assad for allegedly using chemical weapons against civilians in Damascus and elsewhere.
The U.S., which has led a coalition to combat the Islamic State (IS) terror group in eastern Syria, does not have any military presence in northwestern Syria, including Idlib. In the past, however, U.S. officials did voice concerns about the presence of tens of thousands of foreign fighters, including al-Qaida-affiliated terrorists, in the province but cautioned against full-scale military operations, maintaining that doing so would lead to a humanitarian crisis, as the province is home to 3 million people.
"Idlib is essentially the largest collection of al-Qaida affiliates in the world right now," Michael Mulroy, deputy assistant secretary of defense for the Middle East, said this week during remarks at the Center for a New American Security in Washington.
"We have very limited insights as to what's going on," he added.
Idlib is one of several de-escalation zones in Syria that were created in 2017 after trilateral talks among Russia, Turkey and Iran to try to prevent further escalation among warring parties.
U.S. officials have urged Russia and the Syrian regime to comply with their commitments in Idlib, which were to ensure that the zones remain free of escalation.
"The violence must end," Morgan Ortagus, State Department spokeswoman, said in a statement this week. "The United States reiterates that any escalation in violence in northwest Syria will result in the destabilization of the region."
Turkey and Russia reached an agreement last September that prevented a planned Syrian regime offensive on Idlib and other areas near the Turkish border. Turkey assured Russia that the local rebel and militant groups, some of which are allied with Ankara, would not assault Russian and Syrian government forces.
However, HTS's advances in Idlib earlier this year, which led to the terror group's consolidation of power over most of the province, has put an already fragile agreement between Russia and Turkey at further risk.
One point of the Turkey-Russia deal was that Ankara would work to disarm and dislodge the jihadist group and other extremists from Idlib. But Turkey has so far been unable to implement that part of the agreement.
"Turkey has two options. The first one is to give in to Russian demands by entering a war with HTS and its allies," said Ahmed Rahal, a former Syrian army general who is now a military analyst based in Istanbul.
"But this unlikely because the jihadists are based in a civilian area where more 3 million people live. Turkey cannot enter such a war because it would create a major refugee and humanitarian crisis. That's why Ankara is pushing for a diplomatic solution."
The other option for Turkey, according to Rahal, is to yield the way for its allied Syrian rebel forces to enter an open-ended war with Syrian regime troops.
Military buildup or containment?
Pro-regime Syrian media outlets on Thursday reported a continued military buildup by regime troops near the southern part of Idlib, in what appears to be a final preparation for a ground offensive against rebel forces.
But experts say a major offensive carried out by the Syrian regime and its Russian ally is unlikely at this point.
"I don't think the Syrian regime would launch a large-scale ground offensive in Idlib," said Fabrice Balanche, a professor at the University of Lyon in France who is an expert on Syria and follows developments in the country.
He told VOA the ongoing movements of Syrian government forces in south Idlib could be part of the "Syrian regime's policy of containment" to ensure that jihadists would not be able to expand their operations into Idlib's neighboring provinces.
The U.N. has blamed the Russia and Syrian regimes for the damage to a medical center and two hospitals resulting from the airstrikes in northwestern Syria this week.
While thousands of civilians have already evacuated from Idlib and its surrounding areas, the U.N. fears that such military activities could result in a massive refugee crisis in the region.
"Since February, over 138,500 women, children and men have been displaced from northern Hama and southern Idlib," said David Swanson, an official with the U.N. Office for the Coordination of Humanitarian Affairs.
"Between 1 and 28 April, it's estimated more than 32,500 individuals have moved to different communities in Aleppo, Idlib and Hama governorates," Swanson told AFP.