Troops rained shells on the central Syrian town of Daraya on Friday, killing at least one civilian, a day after nationwide violence cost the lives of more than 90 people, a rights watchdog reported.

Amateur video posted on YouTube and distributed by the Syrian Observatory for Human Rights showed medical volunteers trying in vain to treat a bloodied person at Daraya, in the province of Damascus.

Heavy fighting also broke out in parts of the capital itself, said the Britain-based Observatory, adding that regime forces raided one neighbourhood and detained a number of people.

Elsewhere, an explosion targeting a military vehicle killed at least five troops at Maaret al-Numan in the northwestern province of Idlib, it said, adding that soldiers pounded the town, killing two rebels.

In the southern province of Daraa, cradle of the uprising, shelling by regime troops killed one civilian, the Observatory said.

The latest bloodshed came ahead of expected anti-regime protests to call for a "People's liberation war," according to the Syrian Revolution Coordinators Union.

Of the 95 people killed on Thursday, 68 were civilians, 24 were government soldiers and three were rebel fighters, the watchdog added.

It is not possible to independently verify death tolls for the conflict in Syria since the United Nations at the end of 2011 ceased compiling such figures.

However, the Observatory estimates that more than 16,500 people have been killed since the uprising erupted in mid-March last year.