Activists say jihadi fighters have captured a Syrian army base in the northwestern province of Idlib after two days of fighting.

The Britain-based Syrian Observatory for Human Rights and an Idlib-based activist Mohammed al-Sayid say members of the al-Qaida-linked Nusra Front and other rebel factions captured the Wadi Deif base Monday morning.

The capture came a day after rebels and Nusra Front fighters took over seven government checkpoints around Wadi Deir and the nearby base of Hamidiyeh.

The Wadi Deif and Hamidiyeh bases outside the town of Maaret al-Numan have long been prized targets for the rebels, who have launched multiple sieges since 2012.

The Observatory said that at least 15 pro-government troops and eight opposition fighters have been killed in the clashes on Sunday alone.