At least 23 people were reported killed in Syria on Saturday as violence intensified in the eighth month of unrest against President Bashar al-Assad, pushing the death toll close to 4,600, according to a leading activist group.

In a three-hour, night-time battle in the north-western city of Idlib near the Turkish border, seven members of the security forces, five army rebels and three civilians were killed, the Syrian Observatory for Human Rights (SOHR) said.

Five civilians were shot dead by security forces in central Homs province, and a man's body was returned to his family five days after he had been arrested.

The United Nations' top human rights forum has condemned Syria for "gross and systematic" violations by its forces, including executions and the imprisonment of some 14,000 people.

Syrian authorities say they are fighting foreign-backed "terrorist groups" trying to spark civil war who have killed some 1,100 soldiers and police since March.

An "Arab Spring" of revolts - triggered by an uprising in Tunisia in January - has reshaped the political landscape of the Middle East this year and toppled leaders in Egypt, Libya and Yemen.

Syrian opposition groups say defectors from Syria's conscript army are increasing their attacks on government security forces trying to suppress revolt against 41 years of Assad family rule.

Syria faces deepening international and regional isolation, with the Arab League, the European Union and the United States piling on increasingly tough sanctions to pressure Damascus to stop the bloodshed and talk to its opponents.

China and Russia oppose sanctions and last month scuppered Western efforts to pass a U.N. Security Council resolution condemning Assad's government.

The state news agency SANA gave a detailed account of operations by Syrian security forces, including clashes with "terrorists," arrests, the explosion of roadside bombs and the defusing of explosive devices.

It said special forces caught dozens of wanted men in the area of Tel Kalakh who had been smuggling weapons, drugs and armed men from Lebanon into Syria.

Special forces also captured 14 gunmen who, Sana said, had been killing and kidnapping civilians and soldiers.

According to the British-based SOHR, nearly a quarter of the 4,600 on its death toll are from Syrian security forces.

In Deraa, "special forces clashed with armed terrorist groups trying to attack security centers in rural parts of the province. One of the gunmen was killed in the exchange of fire," Sana reported.

"Special forces also clashed with armed terrorists in Idlib after they tried to attack a public roads building and several security detachments. Special forces were able to kill one of the gunmen and wound a number of others. One member of the security forces was injured."

Army engineers in Hama disabled two improvised explosive devices planted in the city, the agency reported.

The Sana correspondent said a source told the agency two other IEDs had exploded, one when a security patrol was passing near a sports stadium, injuring two. The second IED explosion caused no injuries.

In Lattakia, an IED exploded in front of an electrical workshop, starting a fire in which two people died, the agency reported.

The head of the opposition Syrian National Council (SNC), said the isolation of Syria was accelerating and he was pushing for more international intervention against Damascus and seeking Russian support.

Burhan Ghalioun told the Wall Street Journal that he envisioned a post-Assad Syria distanced from anti-Western Iran and Hezbollah and would move closer to the Arab League as well as Gulf states.

Syria has fostered close ties with Tehran since Iran's 1979 Islamic Revolution.

The US accuses Damascus of helping Iran funnel weapons to Hezbollah, a powerful militant movement in Lebanon that fought a 34-day war against Israel in 2006.

"There will be no special relationship with Iran. This is the core issue - the military alliance," Ghalioun told the US paper, though he said he did not oppose maintaining economic ties. "Breaking the exceptional relationship means breaking the strategic military alliance."

With pressure rising against Damascus, only four countries voted against the UN human rights forum's condemnation of Syria which sets the stage for possible action by UN political bodies in New York.

Russia does not want to provide the West with what it believes could be a justification for military intervention in Syria, like the Nato air campaign that helped rebels topple Libya's Muammar Gaddafi in August.

Ghalioun said the opposition is still trying to persuade Moscow that steps such creating a buffer zone, a humanitarian corridor or a no-fly zone to protect civilians would not lead inevitably to armed intervention.

"This is different than the organized military intervention that happened in Iraq for regime change," he said. "We count on Syrians to bring down the Syrian regime...We want the international community to stop the oppression of the Syrian people."

Western powers have shown little appetite for armed intervention in Syria because of the complexity of its sectarian divisions and the risk of escalation posed by its alliance with Iran.-Reuters