BEIRUT - Clashes have broken out in northwestern Syria between two of the most powerful insurgent groups there raising fears of widespread violence in the rebel-held province of Idlib, the groups and an opposition monitor said Saturday.
The fighting between the ultraconservative Ahrar al-Sham and the al-Qaida-linked Hay'at Tahrir al Sham -- Arabic for Levant Liberation Committee -- that is also known as HTS, are the first serious acts of violence since both sides reached a truce in February. Wider clashes between the two former allies could affect their fight against President Bashar Assad's forces who have been gaining ground over the past year under the cover of Russian airstrikes.
Idlib has taken on greater significance in Syria's civil war as opposition fighters and militants head, or are driven, there from the country's central and northern regions. Bordering Turkey, Idlib has welcomed thousands of insurgents who left the country's largest city of Aleppo when it fell to Assad's forces in December in the government's biggest victory since the crisis began in March 2011.
Hundreds of others also headed to Idlib this year from suburbs of the capital Damascus and the central city of Homs as part of population transfer deals with the government.
Ahrar al-Sham said in a statement Saturday that the al-Qaida-linked Levant Liberation Committee is sending reinforcements to the town of Saraqeb and the Jabal al-Zawiya region in preparation for an attack. It accused HTS of acts of "tyranny."
The Ibaa News Agency of HTS accused Ahrar al-Sham of setting up checkpoints and detaining one of its commanders and his bodyguard, adding that HTS removed the checkpoints later by force.
Ibaa quoted an HTS military commander, who was identified as Mouawiyah al-Hashimi, as saying that the two groups agreed to solve the crisis in accordance with Islamic law. He added that Ahrar al-Sham issued its statement about reinforcements after the attempt to solve the latest crisis.
"Our first choice is to resort to Islamic law and solve the problems away from arms and bloodletting," the Ahrar al-Sham statement said. "If the (HTS) command insists on its tyrannical acts .... the movement (Ahrar al-Sham) is ready to repel injustice."
The Britain-based Syrian Observatory for Human Rights said the clashes late Friday were concentrated near the village of Tel Touqan. It added that after the clashes, Ahrar al-Sham briefly cut water supplies to the provincial capital of Idlib that is mostly controlled by HTS.
The lashes come at a time when Ahrar al-Sham is trying to market itself as a moderate rebel group and has been recently raising the main opposition banner -- black, white and green with three red stars in the middle.
HTS is a coalition led by Fatah al-Sham Front that was formerly known as the Nusra Front. The group announced last year it was changing its name to Hay'at Tahrir al Sham and had cut all contacts with al-Qaida to market itself as a Syrian group.
Fatah al-Sham Front and the Islamic State group are considered terrorist organizations by the international community. Still, the al-Qaida-linked HTS enjoys the support of the local population in northwestern Syria where many see it as a powerful faction confronting President Bashar Assad's army and his allies.
On Wednesday, HTS issued a statement saying that two of its members were found killed near the northwestern village of Sarjeh and blamed Suqour al-Sham, a strong ally of Ahrar al-Sham for the killing.
In the northern city of Raqqa, the U.S.-backed Syrian Democratic Forces pressed ahead in their offensive aiming to retake the de facto capital of IS. The attack on the city began on June 6.
IS released a video showing its fighters being trained as snipers to target SDF fighters. The video claimed that 164 SDF fighters had been killed in Raqqa over the past month.
It was not possible to confirm the figure released by IS but SDF has been holding funerals for fighters who died in Raqqa over the past weeks.