UN Syria mediator Staffan de Mistura was preparing a new push for peace on Monday, in meetings in Geneva with regional powers that focus on constitutional reforms in the war-ravaged country.
De Mistura had invited senior officials from Russia and Iran, which back Syrian President Bashar al-Assad, as well as Turkey, which supports rebels, according to de Mistura's office.
Following bilateral talks on Monday, the officials are due to hold a plenary meeting with de Mistura on Tuesday.
UN-brokered talks between the Syrian government and opposition have failed to yield any results in recent years, as government envoys refused to talk about political change and elections, while the opposition demanded al-Assad's resignation.
In January, Russia hosted a conference in Sochi that resulted in a plan for a Syrian constitutional reform committee that would include both sides on the political divide.
The conference was attended by representatives of the Damascus government and the Syria-based moderate opposition.
Although the opposition in exile boycotted this meeting, its representatives have signalled that they would cooperate with such a constitutional committee as long as it would be under UN auspices.
Following his talks with Russia, Iran and Turkey, de Mistura plans to consult with Britain, France, Germany, Jordan, Saudi Arabia and the United States in Geneva next week.
