The UN Security Council has voted unanimously in favour of a Western-drafted resolution to send observers to monitor a shaky truce in Syria.

Russia, a staunch ally of President Bashar al-Assad, which raised earlier reservations over the draft, backed the vote for the first ever resolution on Syria since the uprising against Assad broke out 13 months ago.

UN Resolution 2042 approved sending the first 30 unarmed military monitors, who are expected to leave within days.

An advance team of observers is due to travel to Syria by the end of the weekend.

A new resolution with a full mandate will be required for the monitoring mission of more than 200 observers.

The resolution called on both sides to achieve a sustained halt "of armed violence in all its forms" and urged the Syrian government to "implement visibly" all commitments under special envoy Kofi Annan's peace plan.

This includes the withdrawal of all troops and heavy guns from Syrian cities.

It also called on Mr Assad and the opposition "to guarantee the safety of the advance team without prejudice to its freedom of movement and access," stressing that "primary responsibility" for the observers' safety rests with the Syrian government.

As the vote took place the Syrian Observatory for Human Rights claimed that forces loyal to President Assad had killed four civilians when they opened fire on a funeral procession for a demonstrator in Aleppo.

State television aired footage of youths burning tyres and hurling stones in the Aleppo district of Izaa, and accused gunmen of fanning out in the area and opening fire at random.

The Observatory also claimed that troops had shelled the Jurat al-Shayah and Al-Qarabis districts of the central city of Homs, killing three civilians.

Except for the old quarters in Homs, where dissidents remain active, regime forces control most of the city since they overran the rebel stronghold district of Baba Amr at the beginning of last month.

The rights group also claimed that a civilian was shot dead by soldier manning a checkpoint in Qalaat al-Madiq, while a dissident policeman was killed in a raid by security forces in Jabal al-Zawiya, in the northern province of Idlib.

Farther south, in the town of Dmeir outside Damascus, security forces opened fire on a car, killing one civilian and wounding two, the watchdog said. Meanwhile, it added that two soldiers were killed in an attack on their car in the southern province of Deraa.

The claims cannot be verified due to restrictions on reporting in the country.

The United States' envoy to the UN Susan Rice said new attacks by Syrian security forces raised "serious doubts" about the government's commitment to a fragile ceasefire.

The UN says more than 9,000 people have been killed since the uprising against Assad's regime erupted in March last year, while monitors put the figure at over 10,000.