BBC News reports: Veteran Algerian diplomat Lakhdar Brahimi is expected to be appointed as the new UN-Arab League envoy for Syria, according to diplomats.
If confirmed, he would succeed former UN Secretary-General Kofi Annan, who resigned last week saying he could no longer carry out the role.
A six-point peace plan proposed by Mr Annan failed to come into effect, and violence has escalated.
Rebels lost of a key area of Aleppo on Thursday after weeks of fighting.
The rebel Free Syrian Army (FSA) confirmed it had retreated from the strategic Salah al-Din district in the face of a large-scale government offensive launched the previous day.