At least 11 Islamist fighters and five civilians were killed as a ballistic missile struck a building in northwest Syria during a meeting between rebel groups, AFP reports.
"Eleven fighters from [Al-Qaeda affiliate] Al-Nusra Front and other Islamist groups were killed on Sunday, along with five civilians, when a ballistic missile hit a police station being used as a court in Salqin" in Idlib province, the Syrian Observatory for Human Rights said.
The Britain-based monitoring group said it was unclear if the missile was fired by Russian or Syrian forces.
The monitor said the toll could rise further because a number of people had been seriously wounded in the strike.
The missile struck during a reconciliation meeting between members of Al-Nusra and the conservative Islamist militant group Ahrar al-Sham, who had exchanged fire in the town earlier the same day.
Staunch regime ally Russia began an aerial campaign in Syria last September after a string of government losses, including in Idlib, and has since helped reverse some opposition momentum.