Abdul-Qadir Saleh, prominent Syrian rebel leader, dies from wounds

Syrian rebels were dealt another serious blow when the leader of one of the most prominent units fighting against President Bashar al-Assad's forces died in a hospital last week.

Abdul-Qadir Saleh, who headed the Tawhid Brigades, died from injuries sustained during a government raid last Thursday, according to his group. His death was only announced on Monday.

"We declare the martyrdom of [Abdul-Qadir] Saleh," Tawhid said in a statement. 

His death came on the heels of two other victories for Assad's troops: capturing rebel-held positions in the suburbs south of Damascus and two towns and a military base outside Aleppo.

The Tawhid Brigades is one of the "most effective and organized" units fighting against Assad, with an estimated 10,000 fighters. Under Saleh, the group led a rebel surge last year that captured large parts of Aleppo.

While the brigade cooperated with the moderate Free Syrian Army and Al Qaeda-affiliated Jabhat al-Nusra, it was increasingly at odds with another Al Qaeda-affiliated faction that was foreign-led — Islamic State in Iraq and Syria.

Taking advantage of the infighting between the different factions, Assad's forces, backed by Shia militia from Iraq and the Lebanese group Hezbollah, made advances in the north and east of the contested city.

In recent weeks, Tawhid had lost several rebel bases. Saleh was reportedly working on regrouping his fighters in Aleppo when the government raid began on Thursday night, according to the Syrian Observatory for Human Rights.

Just last week, Saleh told an opposition TV station, "We will not let Iran and Hezbollah advance except on our dead bodies."

The strike that injured Saleh also killed senior brigade officer Abu Tayeb and wounded a spokesman, Saleh Anadan.

Tawhid Brigades' political chief, Abdul-Aziz Salameh, was appointed as Saleh's successor.