Syrian security forces are firing on protesters who staged mass rallies on Friday in defiance of a government crackdown.

Witnesses and activists say at least eight people were killed when forces used live ammunition and tear gas on demonstrators calling for President Bashar al-Assad's departure.

News reports indicate most of the deaths took place near the capital, Damascus, where thousands of people took to the streets after midday prayers.

Protesters have rallied in other cities, including Dara'a, Deir el-Zour and Qamishli. The demonstrations have unfolded on the first Friday of the Muslim holy month of Ramadan.

Meanwhile, more details are emerging about the situation in Hama, a city that has been under a military siege since Sunday. A political activist in the city told VOA on Friday that government forces have been carrying out indiscriminate arrests and killings as they storm homes of activists. But he says anti-government demonstrators rallied on Friday in spite of the crackdown.

There is mounting international pressure against President Assad's violent crackdown. In a statement Friday, U.N. human rights experts urged Syria to stop the killings and “pursue dialogue through peaceful processes.”

On Thursday, U.S. Secretary of State Hillary Clinton said Washington believes more than 2,000 people have been killed in the months-long crackdown. She appealed for a “louder, more effective” international response to the violence.

The Syrian government has blamed much of the violence on what it says are terrorists and militants. The state-run SANA news agency said Friday that unidentified gunmen had ambushed a security patrol near the town of Maarat al-Numan, killing two officers.

President Assad issued a decree Thursday that would allow opposition parties to operate for the first time. The move would be a departure from Syria's single-party system that has been dominated for decades by the Assad family's Ba'ath party.

The U.S. State Department dismissed the announcement as “empty rhetoric.”