At least 23 people, including seven civilians, were killed on Sunday in an explosion at a base for Asian jihadists in northwestern Syria's Idlib city, AFP reports.
Extremist groups fighting in Syria count thousands of Asians among their ranks, including many from central Asian states and members of the Muslim Uighur ethnic minority of China's Xinjiang province.
"A large explosion on Sunday evening hit the base of the Ajnad al-Qawqaz faction in Idlib," said Rami Abdel Rahman, head of the British-based Syrian Observatory for Human Rights. He added that most of the non-civilian casualties were fighters from the group.
He did not specify the cause of the blast, but activists on social media said a car bomb was responsible.
Dozens of people were wounded, particularly fighters, according to Abdel Rahman who said the base was "almost completely destroyed" and that nearby buildings were damaged.
The Ajnad al-Qawqaz group includes hundreds of Caucasian fighters and is battling alongside the Fateh al-Sham Front to repel a Syrian regime advance in the southeast of Idlib province, noted AFP.
Fateh al-Sham used to be known as the Al-Nusra Front, the Syrian affiliate of Al-Qaeda, before cutting ties with Al-Qaeda.
The area of Idlib has seen intense clashes following a regime offensive aimed at seizing a strategically vital highway between Damascus and second city Aleppo.
The Observatory, which relies on a network of activists across Syria, said regime forces had seized more than 60 villages in the area since December 25.
An alliance dominated by Fateh al-Sham now controls much of Idlib province where there are regular car bombings, often blamed on disputes between armed factions.
Some residents blame the Islamic State (ISIS) group for such attacks, although the group has no open presence in the province.