World Bulletin / News Desk

Syria's main opposition group on Thursday insisted President Bashar al-Assad must go as it rejected calls to join forces against ISIL ahead of a meeting with Russia's foreign minister. 

The head of Syria's National Coalition Khaled Khoja is in Moscow for talks with top diplomat Sergei Lavrov as part of a fresh push by Russia to find a way out of the four-year civil war that has cost some 240,000 lives.  

Moscow - one of Assad's few remaining backers - is pushing a plan for a broader grouping than the U.S.-led coalition fighting the ISIL group, to include Syria's government and its allies. 

But Khoja - in Moscow for his first talks since February 2014 - ruled out cooperating with Assad and reiterated demands that the strongman must leave before any transitional government can be set up.

"Bashar Assad has no role in the future of Syria," Khoja said in an interview with the Interfax news agency. 

Saudi Foreign Minister Adel al-Jubeir - a key backer of the Syrian opposition - also rejected calls to work with Assad against ISIL after a meeting with Lavrov in Moscow Tuesday. 

The meeting in Moscow is part of a broader diplomatic flurry that saw Lavrov sit down with Jubeir and U.S. Secretary of State John Kerry in Doha earlier this month. 

As part of the push, Lavrov is expected to meet the head of a newer grouping of opposition figures known as the Cairo Conference Committee on Friday. 

Russia's top Middle East envoy also met Wednesday in Moscow with the head of the Syrian Kurdish Democratic Union Party (PYD) Saleh Muslim to discuss the mooted anti-ISIL coalition and attempts to unite Syria's splintered opposition.

Syria's opposition and Western officials have hinted that Moscow's backing for Assad may be wavering but Moscow insists it remains firmly behind the Syrian leader.