At least 34 jihadist rebels in Syria have been killed by rival rebels, most after being captured following clashes between opposition fighters in the northern Idlib province, a watchdog said on Tuesday.
The report came after the secular Free Syrian Army launched operations recently against radical militant groups, dpa reported.
"The jihadists were executed by other Syrian rebels in Jabal al-Zawya in the past few days," said Rami Abdel Rahman, head of the Britain-based anti-government Syrian Observatory for Human Rights.
The executed militants were mainly foreigners fighting alongside al-Qaeda-linked groups in Syria, Abdel Rahman told dpa.
He added that most of them had been taken prisoner when fighting between rival rebel groups started on Friday.
The fighting, pitting secular and moderate Islamist opponents of Syrian President Bashar al-Assad against al-Qaeda-affiliated militants, has continued in northern and eastern Syria. Dozens of people have been killed.
The Syrian conflict, which has lasted for nearly three years, has resulted in several radical groups imposing strict Islamic rules in areas under their control.
The Free Syrian Army said it was launching a war "against extremism and terrorism" and called on all foreign fighters to leave Syria, saying that their presence helps al-Assad's regime.
"All Arab and foreign fighters ... have helped Bashar al-Assad and regional powers supporting him," the statement said.
"And for those who came to help, we tell them frankly: your love killed us, and harmed our revolution."