The UN’s special envoy for Syria called on the leaders of Russia and Turkey on Tuesday to dialogue to effect a solution for Syria's Idlib.

"To President [Vladimir] Putin and President [Recep Tayyip] Erdogan, you are the ones, who actually were able to talk to each other, make a telephone call, organize a formula that allow the end of that horrible peril not to be the worst," Staffan de Mistura said at a news conference at the UN Office in Geneva.

"[A] telephone call between two of you would make a big difference even before Tehran," he added.

Talks on Syria in the Iranian capital will be held Sept. 7 with Iran, Russia and Turkey.

De Mistura said the situation in Idlib should be carefully evaluated in terms of politics and the military and a sustainable solution is not impossible as an Erdogan and Putin's one-on-one meeting would be effective.

"There has often been in the past occasions for finding a reasonable, logical, non-dramatic solution. That's why I am urging them [to talk]," he remarked.

The priority in Idlib is to protect civilians as women, men, teachers, medical staff, engineers, according to de Mistura, as children have been trapped in the unknown.

Earlier Tuesday, de Mistura held a news conference in Geneva, where he said the organization is worried about a possible operation in Idlib by the Assad regime and its supporters.

Civilians in Syria's northwestern Idlib province, fearing a possible assault by the regime and its allies, are looking to Turkey to ensure the region’s safety.

Residents are urging Turkey to increase the number of observation points in the area with a view to protecting civilians from an attack they believe is imminent.

Located near the Turkish border, Idlib is home to more than 3 million Syrians, many of whom fled from other cities following attacks by regime forces.

In May, Idlib was designated a “de-escalation zone” -- in which acts of aggression are expressly forbidden -- as part of ongoing peace talks in Kazakh capital of Astana.