The Syrian Observatory for Human Rights, a British-based activist group, said security forces killed 15 people across the country on Tuesday, six of them in Homs.
The Arab League monitors were due to return on Wednesday to Homs where crowds have pleaded for them to visit the most violent neighbourhoods.
The Arab League observers arrived in the country on Monday with a mission to determine if Assad is keeping his promise to implement a peace plan to end his military crackdown on nine months of popular uprising.
Al Jazeera television broadcasted protest of Homs live that showed tens of thousands of protesters gathered on Tuesday in the Khalidiya district shouting and whistling and waving white flags. Khalidiya district belongs to Homs where the monitors of Arab League are yet to visit.
One activist held up a sign to the camera that read: “We are afraid when the monitors leave they will kill and bury us.”
Few reports revealed that tanks of Syrian army were removed from the places where Arab League monitors were to visit.
The Arab League observers’ visit in Syria is the first international intervention on the ground in the country since the uprising began. Protesters hope what they witness will prompt world powers to take more decisive action against Assad.
International journalists are mostly banned by Syrian army; therefore it is difficult to give accurate figures of casualties taking place in Syria.