Thousands of Syrians have taken part in protests against President Bashar al-Assad's regime as international envoy Kofi Annan said the situation in the country was "not good."
Opposition activists said thousands took to the streets across Syria after Friday Prayers.
Protests took place in Daraa, Damascus, Homs, Hama, Idlib, Aleppo, Deir Ezzor, and Latakia.
State media said 18 security personnel were killed in roadside-bomb attacks and other incidents.
Meanwhile, an advance team of UN military observers resumed work after the signing on April 19 of a protocol clarifying their mission to monitor the cease-fire brokered by Annan.
Speaking in Geneva on April 20, Annan's spokesman said the week-old cease-fire was "very fragile."
Ahmad Fawzi added that as soon as the UN Security Council adopted a resolution authorizing up to 300 monitors, Annan's office would "deploy very, very quickly."
He said there were currently seven monitors in Syria, with two more expected on April 23, and a team of 30 should be in place within one week.
The Chinese Foreign Ministry said on April 20 that Beijing was willing to contribute to the UN monitoring mission on the ground.
Based on reporting by AP, Reuters, and AFP