DAMASCUS — The UN special envoy for Syria arrived in Damascus on Tuesday to press fresh talks on forming a constitutional committee to revive a stalling peace process to end the eight-year war.

"Pleased to be back in Damascus," Geir Pederson, a seasoned Norwegian diplomat and the fourth UN ambassador to seek an end to the civil war, wrote on Twitter.

His visit, the fourth since taking up the job in January, comes as the regime and their Russian ally have been carrying out deadly bombardment of the rebel-run region of Idlib in northwest Syria.

"Hopeful we can move the political process forward with the constitutional committee as a door opener, and that we can find a way to end the violence in Idlib," Pederson said in the tweet.

His predecessor, Staffan de Mistura, stepped down after a four-year tenure that ended with an abortive push to form the committee to draw up a post-war constitution.

The regime wants to amend the existing constitution, while the opposition have called for a new one entirely.

The committee is to be made up of 150 members, 50 chosen by the regime, the same number by the opposition, and another 50 selected by the UN envoy.

Pro-government newspaper Al-Watan said Pederson was set to meet senior officials from the foreign ministry on Wednesday.

If Damascus accepted Pederson's proposed list, "the committee could start work in September", sources told the newspaper in its Tuesday issue.

Pederson also said he hoped, during his visit, to "continue work on detainees, abductees, and missing persons" since the start of the conflict.

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 Russia and rebel backer Turkey has taken precedence.

With key military backing from Russia, President Bashar Assad's forces have retaken large parts of Syria from rebels and militants since 2015, and now control around 60 percent of the country. — AFP