Reinforcements are being sent to two Damascus suburbs amid a security sweep and dozens of arrests in the capital.
Rami Abdul-Rahman of the London-based Syrian Observatory for Human Rights says hundreds of soldiers and plainclothes policemen are being sent to the capital’s suburbs of Zabadani and Moaddamiyeh.
Tuesday’s move comes a day after Abdul-Rahman said troops shot dead three civilians in central and northern Syria.
He says dozens of people were detained Monday, including in the Damascus suburb of Qadam.
Syrian authorities have unleashed a brutal crackdown in an effort to put down a four-month-old uprising.
Activists expect protests to escalate during the Muslim holy month of Ramadan, which begins next week.