Eleven Turkish-backed Syrian mercenaries were killed over the past few days on multiple fronts in Libya, the London-based Syrian Observatory for Human Rights (SOHR) reported on Monday.
The death toll of Turkish-backed mercenaries fighting alongside the Libyan National Army of the Tripoli-based government has reached 279, including 13 under the age of 18, it said.
The war monitor also said a new group of mercenaries had arrived in Libya, comprising some 260 fighters.
According to SOHR, Ankara has brought a total of 8,510 militants into Libya including non-Syrian mercenaries, while 3,450 others are still in training in Turkey.
Nearly 120 of the fighters, most of whom are from the Sultan Murad Division in Syria, are aged between 16 and 18, the monitor reported.
Turkey has been backing the UN-recognized Tripoli government against the forces of Gen. Khalifa Haftar in Libya.