Syrian President Bashar Assad will not hesitate to use chemical weapons if he is cornered, a senior Syrian official who defected to the opposition told the BBC in an interview published on Wednesday.
Nawaf Fares, ex-ambassador to Iraq and the most prominent Syrian politician to defect to the opposition, commented: "There is information, unconfirmed information of course, that chemical weapons have been used partially in the city of Homs."
Fares also claimed that Assad's regime, dominated by the Shi'ite Alawite sect, is collaborating with Sunni Muslim militants in al-Qaida.
"Al-Qaida is searching for space to move and means of support, the regime is looking for ways to terrorize the Syrian people," Fares told the BBC.
Meanwhile, the UN Security Council will vote on Wednesday on a Western-backed resolution that threatens Syrian authorities with sanctions if they do not stop using heavy weapons in towns, despite a declaration by Russia that it will block the move.
According to the Western-backed resolution, Syria would face sanctions if it does not stop withdraw its troops from towns and cities within 10 days of the adoption of the resolution.
Reuters contributed to this report.