At least 54 people have been killed in three days as rebels stepped up attacks on government-held areas in Aleppo in the run-up to Tuesday presidential election, a monitoring group has said.

The UK-based Syrian Observatory for Human Rights said four people were killed on Monday by rebel mortar bomb and rocket fire on government strongholds in Aleppo, taking the overall death toll since Saturday to 54.

The group's director, Rami Abdel Rahman said the escalation was linked to the presidential election that is expected keep Bashar al-Assad in power. The group's information cannot be independently verified by Al Jazeera.

Syrian rebels have previously threatened to disrupt the voting in government-held areas.

Syrian state television, meanwhile, reported that 10 people were killed on Monday in a car bomb attack in the central province of Homs where government troops have recently made advances.

The truck bomb attack struck the village of Haraqi.

Haraqi is a governemt-controlled village and majority Alawite, the religious community from which Assad's clan hails.

On Sunday the activist group reported that a family of Alawites, including an 102-year-old man, were killed in central Hama province by fighters of the Islamic State of Iraq and the Levant (ISIL).

According to the group, barrel bomb attacks targeting rebel-held areas in Aleppo by the government forces killed nearly 2,000 civilians since Jamuary.