Tribesmen have risen up against the extremist Islamic State group in eastern Syria, forcing it to withdraw from three villages after heavy clashes that killed more than a dozen people.
The violence in eastern Syria came amid tension on the border with Lebanon after an ambush killed dozens of opposition fighters, activists say.
The Lebanese army said in a statement on Saturday that troops also detained Syrian citizen Imad Ahmad Jomaa, who identified himself as a member of Syria's al-Qaeda-linked Nusra Front.
A Lebanese army general said that after Jomaa's capture, gunmen deployed in Lebanon's border village of Arsal near army positions. He said the government sent reinforcements to the area. He spoke on condition of anonymity as he wasn't authorised to speak publicly.
Arsal is home to tens of thousands of Syrian refugees and rebels enjoy wide support among its population. Syria's civil war has spilled over to Lebanon on several occasions, leaving scores dead.
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The tribesmen's rise against the Islamic State group was the first sign of local resistance to the extremists since its fighters captured large parts of the oil-rich eastern province of Deir el-Zour in recent weeks.
The Syrian Observatory for Human Rights and Turkey-based activist Mustafa Osso said the group was forced to bring in reinforcements from neighbouring Iraq after members of the Shueitat tribe drove jihadi fighters out of the villages of Kishkiyeh, Abu Hamam and Granij.
The Observatory, a Britain-based group relying on activists inside Syria, said tribesmen torched the local headquarters of the Islamic State group in the nearby town of Ashara and that residents demonstrated against the group.
Osso and the Observatory said fighting first broke out on Wednesday after jihadis detained three tribesmen, allegedly breaking an agreement between the two sides reached after Islamic State fighters captured the villages.
The al-Qaeda breakaway Islamic State group took over large swaths of western and northern Iraq in June.
The group has declared a self-styled caliphate in territory it controls along the Iraqi-Syrian border.
