"For the opposition, the message is very clear: if they were planning to win the war, facts are proving that is not the case," the 70-year-old diplomat said, adding "now is the time to win the peace."
According to de Mistura, the only way forward is for officials to determine a long-term political solution. If they don't, the country may see a new version of Daesh crop up in their region.
"Victory can only be if there is a sustainable political long-term solution," de Mistura said. "Otherwise instead of war, God forbid, we may see plenty of low intensity guerrilla [conflicts] going on for the next 10 years, and you will see no reconstruction, which is a very sad outcome of winning a war."
Planning to join the sixth round of peace talks in Astana, Kazakhstan, de Mistura is hoping to cement a resolution to help resolve the situation in Idlib in northwestern Syria, where rebels are gaining influence in the city of nearly 2 million residents.
"I am confident… there will be a non-conflictual solution — let's say not a new Aleppo, that's what we want to avoid at any cost, if we have learned from the past," de Mistura urged.
In mid July, Hayet Tahrir al-Sham, a group of rebels previously associated with Al-Qaeda, took control of Idlib after its Islamist allies-turned-rivals, Ahrar al Sham, withdrew from the city and province following a ceasefire.
While previous talks offered little progress, de Mistura, who has been involved in negotiations since January 2016, hopes the next round with be more fruitful.
