ISIS and Al Qaeda's Nusra Front not invited to talks
ISIS and Al Qaeda's Nusra Front not invited to talksReuters

The UN will Tuesday start hosting separate talks with rival sides and "as many stakeholders as possible" in war-torn Syria in a bid to kickstart stalled negotiations to end the four-year conflict.

United Nations peace envoy for Syria Staffan de Mistura will give a news conference around midday Tuesday, kicking off four to six weeks of "separate consultations" with different sides in Syria's four-year conflict, spokesman Ahmad Fawzi said, AFP reports.  

The "low key, low profile" talks will include as many players as possible, including different Syrian factions and regional and international players.

Terror-listed entities like the Islamic State group (ISIS) and Al Nusra have not been invited to the talks, but Fawzi said that groups in contact with them were on the list.  

Iran, which backs President Bashar al-Assad and which has been excluded from two rounds of previous Syria negotiations in Switzerland, has been invited to take part.  

There will be no face-to-face meetings between the different sides, with ambassadors and experts taking part in closed-door separate consultation.  

These aim to take stock of the various sides' positions to allow de Mistura to stake the best way forward, Fawzi said.

"We don't expect any major announcement, we don't expect any concluding communiques that will be signed by everybody," he told reporters.  

De Mistura himself hinted last week that a new round of full negotiations to end the conflict might be possible, perhaps starting late next month.  

In the meantime, he wants the separate consultations to take place out of the public eye, Fawzi said.

It remains unclear whether de Mistura will have more success than his predecessors former UN chief Kofi Annan and Lakhdar Brahimi in ending the conflict that has killed more than 220,000 people since March 2011.

De Mistura, a Swedish-Italian career diplomat who was appointed UN envoy for Syria last July, warned the Security Council last week that prospects for a political transition were slim.

In January, he said conditions were not yet right to try to launch more talks after the two first rounds of negotiations in Switzerland failed.