Syrian government forces fired machine guns and mortar rounds Friday, arch 23 in fierce clashes with rebel army defectors in a town near the Turkish border, a Syrian activist group reported, according to The Associated Press.

The regime however is pressing on with several offensives throughout the country, including in northern areas close to the rebels' main supply bases in Turkey.

The Britain-based Syrian Observatory for Human Rights said the clashes in the town of Azaz in the northern province of Aleppo have left at least three soldiers and one defector dead. The Observatory, which has a network of activists around Syria, said military helicopters were seen flying over the town, eight kilometers (five miles) from the Turkish border.

The Local Coordination Committees, another activist group, said troops were shelling residential areas in Azaz with heavy machinegun fire and mortar rounds.

The Observatory also reported that 24 mortar rounds fell Friday morning in several neighborhoods in the central city of Homs - Bab Dreib, Safsaf and Warsheh. They shells caused damage but it was not clear if there were casualties, it said.

Homs has been the scene of some of the heaviest fighting in the uprising. Government forces crushed a rebel stronghold in Baba Amr neighborhood on March 1 but appear to be facing continued resistance from other parts of the city.

Amateur videos posted online by activists on Friday showed what they said were Soviet-designed T-72 battle tanks driving through streets in the central city of Hama.