The UN special envoy for Syria said he held "successful" talks Monday with Syrian Foreign Minister Walid Muallem on forming a committee to draft a post-war constitution. "Today I have concluded another round of very successful discussions with Foreign Minister Moallem and we addressed all outstanding issues related to the constitutional committee," Geir Pedersen told reporters in Damascus. The diplomat said he also held "good discussions" with Nasr al-Hariri, the head of the Syrian Negotiation Commission opposition grouping. Syrias foreign ministry said the meeting with Pedersen was "positive and constructive", in a statement posted on its social media channels. The UN-backed push to form a constitutional committee has been bogged down by disagreements with President Bashar al-Assads government over the makeup of the body. Damascus hopes to amend the current constitution, while the opposition wants to write a new one from scratch. Last week, the UN Secretary-General Antonio Guterres said an agreement had been reached concerning the "the composition of the committee". The committee is to include 150 members -- a third picked by the regime, another by the opposition, and the remaining third by the United Nations. The Kurdish administration in northeast Syria on Monday decried its exclusion from the committee as "unjust", saying it undermined the principles of democracy. Besides its composition, the mechanisms that will govern the committees work have yet to be agreed on, prompting fears among diplomats that concrete progress is still months away. Numerous rounds of UN-led peace talks have failed to end a war that has killed more than 370,000 people and displaced millions since erupting in 2011 with the repression of anti-government protests. In recent years, a parallel negotiations track led by regime ally Russia and rebel backer Turkey has taken precedence. With key military backing from Russia, Assads forces have retaken large parts of Syria from rebels and militants since 2015, and now control around 60 percent of the country.