Syria's state news agency says assailants have fired rocket-propelled grenades at the Central Bank and a police patrol in the capital Damascus and detonated two bombs in the northwestern city of Idlib.
The SANA agency says four policemen were hurt and the bank building was slightly damaged in Monday's attacks.
A rights activist said more than 20 people were killed, the majority of them members of the security forces, in the explosions in Idlib. "The bombs exploded next to the Air Force Intelligence headquarters and the Military Intelligence building," Rami Abdelrahman, head of the Syrian Observatory for Human Rights, said.
State media blamed Sunday's attacks on "armed terrorists," a term it uses to describe those trying to overthrow President Bashar Assad. A largely peaceful uprising began more than 13 months ago but turned into an insurgency under a regime crackdown.
The UN is trying to make a cease-fire stick, and a Norwegian general arrived in Syria on Sunday to take command of a team of truce observers.
General Robert Mood acknowledged the huge task awaiting the planned 300-strong unarmed mission, which now has 30 people on the ground, but said he was confident it could make headway.
"We will be only 300 but we can make a difference," Mood told reporters on his arrival in the Syrian capital. His comments were passed on to Reuters in neighboring Beirut.
"Thirty unarmed observers, 300 unarmed observers, even 1,000 unarmed observers cannot solve all the problems," he said. "I call on everyone to help us and cooperate with us in this very challenging task ahead."
The United Nations says President Bashar Assad's forces have killed 9,000 people during the revolt, the latest in a string of uprisings in the Arab world against autocratic rule.
Damascus says 2,600 of its personnel have died at the hands of anti-Assad militiamen, and has accused the United Nations of turning a blind eye to "terrorist acts" against security forces.
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