At least 40 bodies of men, women and children were discovered on Saturday in the Syrian town of al-Nabk, a Damascus suburb, in an apparent new massacre, the Syrian Revolutionary Council reported, following a heavy shelling campaign by the regime’s army.
The opposition Syrian National Coalition (SNC) issued a statement hours earlier calling upon countries of the “free world” to “protect civilians in Syria and to intervene immediately” after news of the heavy shelling on Nabk surfaced.
Syrian regime fighter jets also pounded a rebel-held city in the country's northeast, killing at least 12 people including five children, activists said.
The Britain-based Syrian Observatory for Human Rights reported that the air raids hit the northeastern city of Raqqa early afternoon. Four women were among the dead and dozens of people were wounded, the Observatory said.
Rebels captured Raqqa, the capital of the province of the same name, in March. It's the only major urban center to fall entirely under opposition control since the Syrian conflict began in March 2011.
Rebels also control territory in the north and parts of Aleppo, Syria's largest city and its commercial center.
President Bashar Assad's forces have relied heavily on air power in the last year to regain control of opposition-held territory, particularly in the north and along the border with Turkey.
Activists say airstrikes often precede government ground offensives. Assad's troops may be mounting a major operation to recapture territory and bolster its position ahead of peace talks planned for January in Geneva.
Divisions between rebel factions and the increasing influence of radical Islamists in the rebel ranks have strengthened Assad’s position in the more than years of civil war.
The Western backed Syrian Free Army (FSA) announced on Saturday that two of its commanders were killed by the al-Qaeda linked Islamist State of Iran and Syria (ISIS). The two commanders, Mohammad al-Qadi and Ahmad Jahar, were abducted while leading an aid convoy from Turkey to northern Syria.
They were reportedly seen last at an ISIS camp in the town of Azaz, but a day later their bodies were found by residents in the outskirts of Azaz.
Some residents said they were baffled by the “secret execution” of the two men. One resident said the al-Qaeda group usually puts individuals on trial and then executes them publically. “Secret executions are not part of al-Qaeda’s style,” one resident said.
Meanwhile, fighters from the Islamic Front, a union of six major rebel groups, took control of the Free Syrian Army (FSA) bases at the Bab al-Hawa crossing on the northwestern border with Turkey late on Friday night, the opposition sources said.
Louay Meqdad, an FSA spokesman, said the Islamic Front fighters had entered the bases after saying they wanted to help to secure them. They then asked officers and employees to leave and replaced an FSA flag with one of their own, he said, according to Reuters.
"We believe that those brigades are our brothers, that they know that we are not the enemy," Meqdad said.
Infighting among Syria's rebel groups has undermined their fight against President Bashar al-Assad in the 2-1/2-year-old civil war and made Western governments hesitant to back them.