The Syrian Opposition National Coalition (SNC) on Tuesday accused the government of recent use of chemical weapons, saying it will file a report on the matter with UN agencies.

The SNC, Syria's opposition umbrella group in exile, also accused President Bashar al-Assad's administration of committing massacres during the Islamic holy month of Ramadan.

As many as 1700 people were killed this month in 20 different attacks launched by Assad forces, SNC senior member Louay Safi said at a press conference in Istanbul.

"They even targeted civilians performing night prayers at mosques in Homs," Safi said, reiterating SNC's claims that they have enough evidence to prove that pro-Assad forces used chemical weapons.

The SNC has prepared a detailed report that includes all the massacres and abuses by the Assad government against Syrian people during Ramadan, he said.

The report will be filed with UN agencies as well as international human rights organizations.

The Syrian opposition appealed to the international community to take immediate action to protect civilians and bring those responsible for such crimes, including Assad, to the International Criminal Court.