De Mistura told a news conference he wanted to verify the position of international and regional parties to the conflict to ensure there was a critical mass about “what could be a framework of a political transition”.
“The next round of the talks needs to be quite concrete in the direction of a political process leading to a real beginning of a political transition,” he said.
A first round of talks ended on March 24 with de Mistura determined that the Syrian government would move beyond discussing principles and procedure in the next round, which had originally been scheduled to resume on April 9 and was then pushed back to April 11.
De Mistura said he had already heard some interesting ideas from Russia and would also consult Turkish, Saudi, Jordanian and Lebanese officials before the talks resume on April 13.
Syria is holding parliamentary elections on April 13, and the Syrian government delegation would not arrive until April 14 or 15, he said.
The talks have gone hand-in-hand with a cessation of hostilities which has lasted more than a month, raising the prospect of an end to a war that has killed more than 250,000 people and driven many Syrians from their homes.
There has also been a push to improve access for humanitarian aid, which has faltered in the past week.
Jan Egeland, who advises de Mistura on humanitarian issues, said he was “disappointed and disheartened” at the slowdown and called on the Syrian government to live up to its promises to allow aid in.
“April was supposed to be our best month. It’s not looking so, so far,” Egeland said. “We had five convoys ready to go, the last four days. All of the five convoys could not go. 287,000 people therefore did not get the relief, in hard-to-reach areas or in besieged areas.”
However, he said there was hope of an evacuation in the next week of up to 500 people — the wounded and sick and their relatives — from the four towns of Madaya, Zabadani, Foua and Kufreya.