The U.N. special envoy for Syria said Wednesday the Syrian government’s refusal to negotiate on revisions to the country’s constitution is a key reason for the failure of talks last week that left the road map to peace in the conflict-torn country in question..

Geir Pedersen expressed his disappointment to the U.N. Security Council, saying the parties also failed to agree to meet again before the end of the year. But he said he will continue to engage with all “to address the challenges that have arisen,” saying it is urgent to produce results.

Pedersen said the government delegation presented a proposed constitutional text on Syria’s sovereignty, independence and territorial integrity on Oct. 18, representatives of the exiled opposition presented a text on the armed forces, security and intelligence agencies on Oct. 19, while civil society groups submitted a section on the rule of law on Oct. 20. The government submitted a second text on terrorism and extremism on Oct. 21, he said.

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Pedersen said the government and opposition co-chairs were unable to agree on how discussions should progress further at a plenary meeting Oct. 22, but they did agree that the parties, which include civil society representatives, could present further material.

“In that meeting, the delegation nominated by the government stated that it had no revisions to present of its draft constitutional texts and that it did not see any common ground,” the U.N. envoy said.

He said the opposition presented proposed amendments to all the proposals to try to build common ground, and some civil society representatives also presented revised versions.

The end result, Pedersen said, is that the 45-member drafting committee was “not able to move from submitting and discussing initial draft constitutional texts to developing a productive textual drafting process.”

Despite the failure, Pedersen said he remains convinced “that progress on the constitutional committee could, if done the right way, help to build some trust and confidence.”

“But let me stress that this requires real determination and the political will to try to build some common ground,” he said.

The talks last week followed a nine-month hiatus in the U.N.-led meetings of the Syrian constitutional committee.

Syria’s 10-year conflict has killed between 350,000 and 450,000 people and displaced half the country’s pre-war population of 23 million, including more than 5 million refugees mostly in neighboring countries. Even though the fighting has subsided in recent months, there are still pockets controlled by Syrian opposition, where millions of people live.

Pedersen said that while the talks were under way, violence continued, including terrorist attacks, airstrikes and heavy artillery shelling that caused casualties, including dozens of civilians. He said some incidents “also underlined the constant risks of regional escalation” and again called for a nationwide cease-fire.

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The U.N. envoy said more than 12 million Syrians remain displaced, either inside the country or as refugees elsewhere, and the level of poverty is around 90%.

At a Russia-hosted Syrian peace conference in January 2018, an agreement was reached to form a 150-member committee to draft a new constitution, with a smaller 45-member body to do the actual drafting including 15 members each from the government, opposition and civil society. It took until September 2019 for the committee to be formed.

A 2012 U.N. road map to peace in Syria approved by representatives of the United Nations, Arab League, European Union, Turkey and all five permanent Security Council members calls for the drafting of a new constitution and ends with U.N.-supervised elections with all Syrians, including members of the diaspora, eligible to participate. A Security Council resolution adopted in December 2015 unanimously endorsed the road map.

The United States and several Western allies have accused Syrian President Bashar Assad of deliberately stalling and delaying the drafting of a new constitution until after a presidential election in late May to avoid a U.N.-supervised vote, as called for by the Security Council. Assad was re-elected in what the government called a landslide for a fourth seven-year term, but the West and the Syrian opposition called it an illegitimate and sham election.