Syria, meanwhile, blamed "armed groups" for the casualties and put the toll at 17.
The National Organization for Human Rights in Syria, whose leader Ammar Qurabi is currently in Turkey, said most of the deaths occurred in the northern province of Idlib and the central region of Homs.
Yesterday, thousands of Syrians defied an unrelenting government crackdown and flooded the streets across the country to buttress their two-month uprising against the country's authoritarian regime. Authorities responded with live ammunition, causing the large number of casualties, right groups say.
The latest deaths bring to at least 900 the number of civilians killed since the uprising began, according to human rights group tallies. A lower toll from the latest clashes came from Syria's state-run news agency, SANA.
SANA said today that "armed groups who took advantage of peaceful gatherings" shot dead 17 civilians, policemen and members of the military on Friday in Idlib and Homs.
SANA quoted an unnamed Interior Ministry official as saying an armed group also attacked several police stations and vehicles in Homs and Idlib.
The government repeatedly has blamed the unrest on armed gangs not true reform-seekers.
Syria has banned foreign journalists and prevented local reporters from covering trouble spots, making it nearly impossible to independently verify witness accounts.
Meanwhile in Lebanon, a security official said thousands of Syrian troops deployed on Lebanon's northern border preventing the flow of Syrian refugees into the country. The official said that after the army's deployment, Syrians can only cross through official border points rather than enter Lebanon illegally.
The official, who spoke on condition of anonymity in line with regulations, said some 10,000 Syrians have fled to Lebanon since the Syrian army began an operation in the western town of Talkalakh, near Lebanon's border, last week.
The turnout for Friday's demonstrations and the now-familiar, deadly response by the regime was the latest sign the conflict could be moving toward a dangerous stalemate with neither side able to tip the scales.
Assad's forces have unleashed tanks and snipers and made thousands of arrests to break the revolt, but protesters continue to face down security forces.