An explosion at a base for Asian extremists in north-western Syria's Idlib city on Sunday (January 7th) killed 23 people including seven civilians, AFP reported.

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 Syrian Observatory for Human Rights head Rami Abdel Rahman, adding that most 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.

Ajnad al-Qawqaz includes hundreds of Caucasian fighters and is battling alongside Tahrir al-Sham, an extremist alliance dominated by the former al-Nusra Front, to repel a Syrian regime advance in the south-east of Idlib province.