Activists say Syrian security forces have moved against several schools around the country and detained students who demonstrated against President Bashar Assad's regime.
The Local Coordination Committees, an activist network, says dozens of students were detained Wednesday in the southern village of Jassem.
Also, security forces surrounded several schools in the Damascus suburbs of Harasta, Arbeen and Zamalka.
Students have been demonstrating against Assad's regime since Sunday, the first day of the school year.
The Syrian uprising began in mid-March, during the wave of protests in the Arab world that toppled autocrats in Tunisia, Egypt and Libya.
President Bashar Assad has responded with a brutal crackdown that the UN estimates has killed some 2,600 people.