Syrian security forces on Saturday arrested 31 people in the course of a military operations to hunt down defectors in northwestern province of Idlib, near Turkey, said the Syrian Observatory for Human Rights in a statement received in Nicosia.
"Since dawn, Syrian security forces have conducted a search and arrest campaign in and around the [Idlib village of] Kfar Nubul looking for intelligence officers who deserted," the Britain-based watchdog said.
The Local Coordination Committees, an activist network spurring protests on the ground, said gunfire was heard in several towns in Idlib, citing reports of defections in the area and a night demomnstration broken up by security forces.
In the flashpoint central city of Homs, military and security forces backed by armoured vehicles stormed the Qusayr neighbourhood, raiding random houses, the same source said.
And gunfire rocked "most of the neighbourhoods" in the flashpoint southern city of Daraa, where the movement calling for greater freedoms and the fall of the Assad regime started in March.
Pro-democracy activists reported 12 people killed on Friday when security forces opened fire on protests in support of army defectors in several cities.
Syrian security forces have pursued an unrelenting crackdown on dissent, with violence typically peaking on Fridays, when the main weekly Muslim prayers serve as a springboard for anti-regime protests.
But they are facing mounting armed resistance and defections, the Observatory has said, with clashes between soldiers and defectors, leaving 36 dead, including 25 soldiers on Thursday alone.
UN human rights chief Navi Pillay said on Friday that the toll from seven months of violence in Syria had risen above 3,000. She said Syria risked "a full-blown civil war" unless the international community took action.
Heeding that warning, envoys for Germany, France, Britain and Portugal raised President Bashar al-Assad's deadly assault on protesters during closed-door consultations at the UN Security Council on Friday.
Russia and China last week vetoed a resolution which had raised the prospect of potential measures against Damascus.
"The advocates of inaction on Syria should draw conclusions from the latest appalling developments," French UN ambassador Gerard Araud told the closed meeting, according to diplomats.
His comments were a veiled attack on Russia and China, but also South Africa, Brazil and India which abstained in the Syria vote last week, diplomats said.
Envoys from Germany, Britain and Portugal also said the UN Security Council must take action on Syria, diplomats said.
Russia and China have insisted the Security Council should not be moving toward sanctions.
China's envoy told Friday's meeting that Pillay's statement should not have been discussed at the Security Council, the diplomats said. Russia also objected to discussion on Syria.
Russia has distributed its own draft resolution which mainly calls for a negotiated settlement, but angered the European nations and Washington because it gave equal criticism to the opposition violence and killings by security forces.
The six Arab states of the Gulf, meanwhile, have demanded an emergency meeting of Arab foreign ministers on Sunday to discuss the unrest in Syria, an Arab League official in Cairo said.
The 22-member League has not yet approved the request but such meetings need the approval of only two members to take place.