US Secretary of State John Kerry and top envoys from 10 other countries are raising the pressure on Syria’s main opposition group to attend peace talks that would bring it face-to-face with the Syrian government.

The two-day meeting begins Sunday in Paris, just a week before the scheduled talks in Geneva.

The Western-backed Syrian National Coalition is nearing collapse, hampered by infighting, international pressure and disagreement over whether to negotiate with Syria’s president, Bashar Assad.

The moderate rebels find themselves battling on two fronts — against al-Qaida linked militants on one side and Assad’s forces on another. But despite low expectations for the Geneva peace conference, diplomats say it is the only chance of ending fighting that has killed more than 130,000 people.

On Sunday, Syrian activists said government shelling has killed more than 20 people in the central city of Homs.

The British-based Syrian Observatory for Human Rights said that the number is expected rise because dozens of people were critically wounded in the shelling of the rebel-held Waer area of Homs.

The Observatory said the shelling occurred Saturday. The activist collective, the Local Coordination Committees, also published similar information.

Forces loyal to Syrian President Bashar Assad have been widening an air assault on rebel-held areas in recent weeks, targeting opposition-held residential areas and killing civilians.

Syrian rebels have also targeted Assad-loyal areas with indiscriminate mortar fire. On Sunday, Syria’s state media said rebel-fired mortar shells killed two people in the Assad-loyal Zahra area of the city.

Copyright 2014 The Associated Press.