Syrian activists say government forces killed at least 52 civilians in attacks across the country Saturday, as Syria's main exiled opposition group met in neighboring Turkey to pick a new leader to unify the movement.

The London-based Syrian Observatory for Human Rights said Saturday's highest death toll was in Daraa, with 20 people killed in a pre-dawn bombardment of the southern town where a pro-democracy uprising began 15 months ago.

Activists said more people were killed in government shelling of the rebellious central city of Homs, and early-morning gunbattles between government and rebel forces in central Damascus. The casualties could not be independently confirmed.

Members of the opposition Syrian National Council who were meeting in Istanbul said the front-runner to become their new leader is Abdulbaset Sieda, a Kurdish human rights activist. The exiled group was expected to meet again Sunday to try to name the successor to Burhan Ghalioun, who agreed step down last month under criticism of his leadership.

The SNC has been plagued by infighting since it was formed last year to try to present a credible alternative to the autocratic government of Syrian President Bashar al-Assad. Ghalioun's critics complained that he gave Syrian Islamists too powerful a role in the SNC and did not do enough to coordinate with committees of youth activists organizing protests inside Syria.

Speaking at Saturday's meeting, Sieda said the SNC should continue to reform itself to better connect with the domestic opposition and serve as the “real representative” of the Syrian people.

In other developments, Russian Foreign Minister Sergei Lavrov said Saturday that Moscow would support Mr. Assad's departure from power if the Syrian people agree on it. Russia has been a longtime ally of Mr. Assad and has repeatedly blocked Western and Arab efforts to impose U.N. sanctions on his government.

It was not clear if Lavrov's comment marked a softening of Russia's support for the Assad government. Speaking at a Moscow news conference, Lavrov also reiterated Russia's rejection of any foreign military intervention in the Syrian conflict. He also repeated his call for nations supporting and opposing Mr. Assad to join an international conference to salvage a Syria peace plan drafted by U.N.-Arab League envoy Kofi Annan.