Activists say Syrian security forces have opened fire at protesters who streamed into the streets after Friday prayers.
The activists say there is no immediate word on casualties.
The London-based Syrian Observatory for Human Rights says intense shooting was heard around the Rawda mosque in the eastern city of Deir el-Zour.
Syria-based rights activist Mustafa Osso says thousands poured into the streets of predominantly Kurdish northeastern towns such as Qamishli, Amouda, and Derbasiyeh.
State-run TV said a policeman was killed and four wounded Friday when they came under fire in the village of Busra Hariri in the southern province of Daraa.
A popular uprising began in Syria in mid-March. President Bashar Assad has reacted with deadly force that the U.N. estimates has left some 2,600 people dead.