At least nine people were killed, including five civilians, according to the UK-based Syrian Observatory for Human Rights. Turkish media earlier reported up to 20 wounded.
The location of the blast was in the center of the city at the People's Market near Kawa Square, ANF news reported. The agency is close to the predominately Kurdish Peoples' Protection Units (YPG).
They reported a car bomb had exploded. The city is currently occupied by the Turkish military and its proxy loyalists.
Local pro-YPG activists tweeted video of the aftermath. They said it targetted "mercenaries of the Shami Front." The group is aligned with Turkey.
الانفجار الذي حصل قبل قليل في #عفرين استهدف مقر مرتزقة الجبهة الشامية التابعة للاحتلال التركي.#شبكة_نشطاء_عفرين
— afrin activists (@afrinactivists) December 16, 2018
The bombing that took place today in #Afrin targeted the headquarters of mercenaries of the Shami Front of the Turkish occupation.#Afrin_Activists_Network pic.twitter.com/ndm5xwAL4Y
No group has claimed the blast.
Turkey ousted the YPG in March, but the group has vowed to retake the western-most canton of Afrin.
