A Syrian rights group says 26 protesters have been killed in the southern city of Deraa after security forces opened fire on a peaceful gathering of protesters.
The National Organisation for Human Rights in Syria also says two people have been killed at a protest in the central province of Homs.
It says security and police forces had dispersed peaceful gatherings in a number of Syrian provinces by using what it calls excessive and unjustified violence through the use of bullets.
However, State TV said that 19 members of the security forces had been killed "by armed groups" in Deraa.
There are also unconfirmed reports of deaths in Homs, Duma and Harasta, as protests swept the country.
The BBC reports Deraa has been a focus of unrest since anti-government protests erupted across Syria in mid-March, challenging the rule of the President Bashar al-Assad.
The president has offered to consider reforms, but opponents say his proposals do not go far enough.
Syria is one of several countries in the Middle East and North Africa to be hit by a wave of protests following popular uprisings in Tunisia and Egypt that unseated long-standing autocratic rulers.
The BBC reports that activists estimate that more than 130 people have died in four weeks of clashes, most in Deraa and Latakia.
Officials say the death toll is nearer to 30 and they blame the violence on armed groups and foreigners seeking to divide the country.