BEIRUT — Syrian troops fired on protesters yesterday in the restive city of Homs, as Arab League observers toured the area to see whether President Bashar al-Assad’s regime is abiding by its pledge to halt its 10-month-old crackdown on dissent, activists said.

In the capital, Damascus, thousands held prayers for those killed since the uprising began in March.

“Enough killings in our beloved Syria,” the country’s top Sunni clergyman, Grand Mufti Ahmad Badreddine Hassoun, told the crowd at the prayer service. His son was shot dead in October.