DAMASCUS: Syrian security forces carried out a spate of raids in Damascus on Tuesday after a deadly bombing hit the capital and UN chief Ban Ki-Moon warned the search for peace was at a “pivotal moment.”

State television said the late Monday blast hit a restaurant in the Qaboon neighbourhood of the capital, with the Britain-based Syrian Observatory for Human Rights saying five people were killed.

In all, at least 59 people were killed nationwide on Monday, including 31 loyalist troops who died in clashes with rebel fighters, the Observatory said.

The bloodshed raged despite the deployment of a UN military observer mission to oversee a promised ceasefire that has been breached daily since it went into force on April 12.

Gunfire erupted as a team of UN observers visited the town of Busayra in Deir Ezzor province in the northeast, activists reached by Skype told AFP.

“Unconfirmed reports indicate there are two dead and several wounded,” one activist said.

The Observatory also said there were also fierce clashes between regime forces and rebels in the town of Kfar Roma in Idlib province in the northwest, with four soldiers killed.

And it said regime helicopter gun ships reportedly opened fire in certain parts of Idlib, wounding an unknown number of people.

Demonstrations broke out at dawn in several neighbourhoods of Aleppo, the country's second city and commercial hub which until recently had been largely spared the unrest shaking the country since March 2011.

One person was killed by gunfire in Nouaymeh, a town in the southern province of Daraa, the Observatory said.

The UN chief issued a new warning on the dangers of all-out civil war as the 14-month uprising against President Bashar al-Assad's regime has turned into an armed rebellion.

“The secretary general said we were at a pivotal moment in the search for a peaceful settlement to the crisis and that he remained extremely troubled about the risk of an all-out civil war,” a spokesman said at a NATO summit in Chicago on Monday.

Nato states have come under criticism for backing the air war in Libya last year that helped insurgents defeat Moamer Qadhafi's forces but ruling out military intervention in Syria.