Head of Medical Service Chemical Corps Syria Abdel Tawab Shahram is to announce his transition to the side of the opposition forces, reports British television channel "Sky News". He will make a statement at a press conference in Istanbul at 17:00 local time (14:00 GMT).
Channel notes that Shahru is also head of the Department of Forensic Medicine of the city of Aleppo.
"Sky News" reports that he supposedly has evidence of the use of chemical weapons troops of Syrian President Bashar al-Assad in the village of Khan al-Asal in March.
Voice of Russia, Sky News, Guardian