Reuters reports the United Nations peace envoy to Syria is holding talks with the Syrian opposition in Turkey to promote a ceasefire proposal for the northern city of Aleppo, opposition sources said on Monday. Staffan de Mistura hopes the plan will establish truces in Aleppo, once Syria's commercial center and second-most-populous city, and allow aid into rebel districts. Aleppo has been split roughly in half between opposition groups in the east and government troops in the west, with the remaining civilians subjected to barrel bombing campaigns. The fighting has severely restricted access for humanitarian aid. De Mistura met on Sunday with Hadi al-Bahra, head of the western-backed National Coalition for Syrian Revolutionary and Opposition Forces, in Istanbul, according to Badr Jamous, a senior member of the opposition body who was also present at the three-hour meeting.