Syrian security forces struggled to contain nationwide protests by tens of thousands of opponents emboldened by the presence of an Arab League observer team.

Fridays have become a day of protest in Syria during the months-long uprising against the regime of president Bashar al-Assad, with activists calling for a “crawl to the squares” yesterday. They encouraged demonstrators, usually confined to suburbs and side streets by sniper fire and roadblocks, to occupy city centres.

Protesters estimated at least 26 people were killed and many others hauled away by the security forces, which appeared largely successful in preventing large rallies in the central squares of cities including Homs, Hama and Deir Ezzor. But activists reached by telephone said the presence of the monitors, and the global scrutiny they have brought, has given them breathing space.