Arab League peace observers, inspecting hotspots across Syria, have called on the government to remove "immediately" snipers from rooftops of buildings, a source close to the delegation told dpa on Saturday.

"The observers saw the snipers with their own eyes in Douma," the source said, referring to a restive town on the outskirts of the Syrian capital, Damascus.

The Syrian government Friday positioned snipers on rooftops and deployed forces across the dissident areas after opposition leaders called for mass protests, according to activists.

The observers are in Syria to verify the government's compliance with an Arab League peace plan, which includes removing military hardware from civilian areas and releasing detainees from prisons.

More than 5,000 people have been killed in the Syrian government's crackdown on a pro-democracy uprising since it started in mid-March, according to the United Nations.

Activists in Idlib, near the Syrian-Turkish border, said that the Syrian army had hidden tanks as a team of observers was inspecting the province.

"They pulled the tanks from the main streets as the team was passing by the area. They brought them back after the monitors left," Omar Idlibi, a Syrian activist, told dpa.

"This regime is maneuvering to cover up realities on the ground," Idlibi added.