Iranian President Hassan Rouhani and his Russian and Turkish counterparts, Vladimir Putin and Recep Tayyip Erdogan, will discuss various issues related to the Syrian crisis in a summit in Tehran on Friday. The topics of discussion will include provocations with the alleged use of chemical weapons, a Putin adviser said.

Speaking to the Izvestiya newspaper, Yury Ushakov pointed to the agenda of the Tehran summit saying the trilateral meeting will cover a wide range of issues related to the settlement of the Syrian crisis and aggravating points, including preparations for provocative moves through using chemical weapons in a residential area of Idlib Province.

The Kremlin aide further said on the sidelines of the summit, Putin will hold separate bilateral meetings with his Iranian and Turkish counterparts.

The remarks came as some Israeli reports said Tel Aviv believes that the fate of Idlib will be determined in the Tehran summit.

In April, the presidents of Iran, Russia and Turkey - the three guarantor states of de-escalation zones in Syria - held a meeting in Ankara to discuss ways for peaceful settlement of the crisis in Syria.

The three countries have so far held several rounds of peace talks in Kazakhstan’s Astana and elsewhere to help end the conflict in Syria. The fourth round of those talks in May 2017 produced a memorandum of understanding on de-escalation zones in Syria, sharply reducing fighting in the country.

Diplomatic efforts to end fighting in Syria gained momentum in 2017 with the announcement of a ceasefire in the Arab country in early January.

According to a report by the Syrian Center for Policy Research, the conflict has claimed the lives of over 470,000 people, injured 1.9 million others, and displaced nearly half of the country’s pre-war population of about 23 million within or beyond its borders.