The United Nations Special Envoy for Syria Staffan de Mistura is set to hold talks with foreign ministers from Iran, Russia and Turkey in Geneva to discuss setting up a committee to draft a new constitution for the war-torn country.

The high-level officials will be seeking the UN’s blessing on their joint proposal on Tuesday and they are expected to propose names for the constitutional committee.

The meeting comes after diplomats from the three countries, who support different sides of the war – now in its eighth year – said on Monday they are close to an agreement to form a committee.

The talks are meant to form a “credible, balanced, and inclusive” committee to draft a new constitution for Syria and usher in elections, a UN statement read last week.

De Mistura, who announced he would be stepping down by the end of the year, has tried since January to clinch an agreement on the identity of 150 members of a new constitutional committee to revitalise a dormant peace process following a Russian-hosted Syrian peace conference in the Black Sea resort of Sochi.

Syrian President Bashar al-Assad‘s government and the fragmented opposition fighting to topple him have each submitted a list of 50 names, but the three nations have haggled over the final 50 members from civil society and “independent” members, diplomats said.

“The three countries are coming with a proposal for the third list, which has been the heart of the problem,” said one diplomat.

Turkey and other nations would consider working with Assad if he won a democratic election, Turkish Foreign Minister Mevlut Cavusoglu said on Sunday, two days before visiting Geneva to meet Russian counterpart Sergei Lavrov and Iran’s Javad Zarif.

Turkey supports opposition fighters, namely, the National Liberation Front (NLF), an umbrella organisation of Turkey-backed rebels that includes the Free Syrian Army.

They control Idlib, the last rebel-held bastion in northwest Syria, and have agreed to comply with a Russian-Turkish agreement to withdraw heavy weaponry from a buffer zone that stretches from neighbouring Latakia’s northern suburbs all the way to the outskirts of Aleppo’s northwest region.

The zone has managed to stave off a large-scale assault on Idlib by the Syrian government and Russia by creating a 15-20km buffer zone last October.

‘Heavy pressure’

De Mistura said the constitutional committee could be a starting point for political progress.

“It does touch, for instance, on presidential powers, it could and should be touching on how elections are done, on division of power, in other words, a big issue,” he said.

De Mistura will be under “heavy pressure” to accept the trio’s proposal to complete the make-up of the constitutional body, but may leave the decision to UN Secretary-General Antonio Guterres in New York later this week, the diplomats noted.

“The last word is with us, with the UN, not with any country, as good and as powerful as they may be,” he said on Sunday.

Last month, Syria’s warring sides and mediators meeting in Kazakhstan failed to agree on the formation of a constitutional committee.

Assad previously said his government would only consider amendments to the current constitution, in defiance of the Sochi agreement to have the government, opposition and independents draft a new document.

Syria’s war has killed more than 360,000 people since it started in 2011 with the police crackdown on anti-government protests.

The Syrian government has regained control over the majority of the country’s territory since the Russian military intervened in 2015, backing Assad’s government.