At least 20 rebel commanders, most of them hardline Islamists, have died in Syria since early December in a string of mysterious targeted killings, a monitor said on Wednesday.
The commanders have been killed in roadside bombs or shootouts, but no faction has claimed responsibility for their deaths. AFP reports that analysts believe they could be part of an assassination campaign carried out by either the regime of President Bashar al-Assad or ISIS.
On Tuesday, Abu Rateb al-Homsi, a provincial "emir" in the Ahrar al-Sham hardline opposition group, was killed when unknown attackers fired on his car in the central province of Homs, according to the Syrian Observatory for Human Rights.
Homsi is the most high-profile of those killed, most of whom come from the ranks of Al-Qaeda's Syria affiliate Al-Nusra Front and hardline groups like Ahrar al-Sham.
"The assassinations have intensified since the beginning of December, but it's unknown who carried them out," said Observatory head Rami Abdel Rahman.