BEIRUT (AP) — Syrian security forces opened fire at protesters in several parts of the country on Friday, killing at least eight people and wounding scores, while a leading opposition figure was beaten up by pro-government gunmen and rushed to a hospital in Damascus, activist said.

The developments came as tens of thousands marched in the streets of several Syrian cities, towns and villages, calling for the downfall of President Bashar Assad’s regime.

The London-based Syrian Observatory for Human Rights said at least four people were killed and 25 were wounded in the central city of Homs, Syria’s third largest city. It also reported intense shooting in the eastern city of Deir el-Zour near the border with Iraq, and the Damascus suburb of Douma.

In Douma, the Observatory said at least three people were killed and several were wounded, while five were wounded in the northern town of Maaret al-Numan.

Syria-based rights activist Mustafa Osso said one person was also killed in the town of Zabadani near the border with Lebanon.

Meanwhile, Riad Seif, a former lawmaker who became a leading opposition figure and outspoken critic of Assad’s regime, was beaten up outside a mosque in the central Damascus suburb of Midan, according to two Syria-based activists.