Fighting raged on Friday between army deserters and forces loyal to President Bashar al-Assad, monitors said, as activists called for massive protests in support of arming the rebellion.
The Syrian Observatory for Human Rights said that fierce battles were taking place in the villages of Al-Tiba, Al-Qabu and Shniyeh in central Homs province.
The fighting broke out after militias loyal to Assad opened fire on a group of seven women, killing two and wounding four, the Britain-based Observatory said in a statement.
It said regime forces were pounding districts of Homs city and that the encircled town of Rastan to the north was being bombarded with mortar rounds and heavy machinegun fire.
The monitoring group also said the body of a man arrested some hours earlier was recovered at Khan Sheikhun in the Idlib region of the northwest.
Elsewhere, security forces launched search operations in Damascus suburbs after a night of clashes with deserters in which three soldiers were killed, the Observatory said.
And at Douma near the capital, it said security forces were attacking the Abdel Rauf district, where the sound of explosions and firing could be heard.
Friday's clashes came after the UN Security Council, including Russia and China, stepped up pressure on Assad's regime to implement a plan to pull its forces out of urban areas, ahead of an April 10 truce deadline.
On its Facebook page, the Syrian Revolution 2011 activist group urged Syrians to take to the streets on Friday in support of arming the rebel fighters, a day after violence killed 77 people across the country -- among them 45 civilians.
The United Nations says more than 9,000 people have been killed in the Syrian regime's crackdown on the year-old uprising that began with massive pro-reform protests on Fridays after the weekly Muslim prayers.
Activists say more than 10,000 people have been killed.
The number of people at the demonstrations has fallen in recent weeks, however, as regime forces have seized major protest centres such as the central city of Homs and Idlib in the north.