Syrian tanks on Wednesday shelled Bab Amr area in the third largest Syrian city of Homs, witnesses said.
The pan-Arab al-Jazeera TV cited activists as saying an armed confrontations took place during the night as the army set up check-points at the entrances of the area, Xinhua reported.
Homs, 160 km north to the capital Damascus, saw clashes between protesters calling for change and the security forces, which led to dozens of deaths.
Syria has been wracked by more than seven weeks of protests urging sweeping reforms. The authorities blamed the violent acts on "armed terrorist groups."
According to Syrian human rights groups, 800 Syrians at least were killed so far, while 9,000 others have been jailed or gone missing.
On Tuesday, the European Union (EU) said an arms embargo and sanctions against 13 Syrian officials deemed responsible for violence against protesters have just come into force. Syrian President Bashar al-Assad has been excluded from the sanctions.