BEIRUT - Syrian protests after weekly prayers on Friday will be the first major test for a UN-backed ceasefire, the head of the main opposition group said on Thursday, adding that the truce remains fragile as long as the army is deployed in urban areas."The Syrian people will go out tomorrow and it will be the biggest possible (demonstration) so that the Syrian people can express their will," Burhan Ghalioun told Reuters by telephone. Ghalioun said the world should be skeptical of Syrian President Bashar Assad's commitment to the ceasefire, which came into effect at dawn on Thursday after weeks of bombardment by Assad's forces against opposition strongholds."We will see tomorrow if (the government) will keep its commitment. While we call on the Syrian people to protest strongly... we ask them to be cautious because the regime will not respect the ceasefire and will shoot," Ghalioun said.The main weekly Muslim prayers on Friday have been a rallying point for protesters throughout the year-long uprising against Assad."I see that this is a fragile ceasefire as long as the weapons are still in the street and not pulled back," Ghalioun said, adding that the Syrian Defense Ministry had warned it remained on alert with "its hand on the trigger."The ceasefire brokered by international mediator Kofi Annan is the first in 13 months of protest and insurgency in which the United Nations says more than 9,000 people have been killed by Assad's forces. Authorities blame the violence on foreign-backed Islamist militants, who they say have killed 2,600 soldiers and police."I think the international community and Kofi Annan should deal with caution, and also the Syrian people should be careful," Ghalioun said.