BEIRUT – The Saudi-backed Syrian opposition has reiterated demands for a halt to bombardments of civilian areas and the lifting of blockades on besieged towns and villages before the start of peace talks in a letter to the U.N. secretary general.

The letter from the High Negotiations Committee to Ban Ki-moon was sent after a meeting on Tuesday during which it discussed an invitation to join peace talks which U.N. envoy Staffan de Mistura aims to convene on Friday.

An opposition official confirmed the authenticity of a copy of the letter published by a pro-Syrian opposition website.

The letter from HNC coordinator Riad Hijab also demanded the release of prisoners, particularly women and children. The steps are mentioned in a U.N. Security Council resolution passed last month endorsing the Syrian peace process.

For negotiations to succeed, the letter said the Security Council should do everything required to put a stop to anything that obstructs “the implementation of Security Council resolution 2254”.