Syrian government forces killed at least 36 people on Friday when they opened fire at demonstrations after activists called for a no-fly zone to protect civilians and soldiers deserting the army, a rights group said.

The security forces opened fire at demonstrations which started after Friday prayers in Hama and Homs, a city of one million, 140 km north of Damascus, despite a heavy military presence, activists and residents said.

They said protesters called for international protection from Nato, whose war planes played a vital role in the overthrow of Libyan leader Muammar Gaddafi.

Similar rallies took place across Syria after prayers, the activists said. The protests, calling for President Bashar al-Assad to quit, were energiserd by Gaddafi's death last week.

Gaddafi had close links with Assad, who has sent tanks and troops to put down seven months of street protests demanding an end to 41 years of Assad family rule.

An armed insurgency has also emerged in the last several weeks, mainly in rural regions and in Homs, where the army and militiamen loyal to Assad have been assaulting old neighbourhoods that have been scene of regular protests.

The Assad government says it intends to carry out political reform and that the unrest is fomented by militants trying to wreck the programme. More than 1,100 soldiers and policemen have been killed in the violence, it says.

Local residents said helicopters fired machineguns and rockets at residential neighbourhoods of Homs this week in an escalation of the military operation. The authorities have barred independent media from the city, making confirmation impossible.

'God, Syria, We want a no-fly zone over it,' shouted protesters in the Bab Tadmur neighbourhood of Homs.

'A no-fly zone is a legitimate demand for Homs,' read banners carried by protesters in the Khalidya neighborhood.

In Hama, activists and one resident said Assad loyalists fired at a demonstration demanding his overthrow as soon at it broke out from Abdelrahman Bin Aouf mosque.

'They attacked the protest immediately because the mosque is near the old Hamiuidya neighbourhood and they did not want the two protests to meet,' said one activist, who did not want to give his name for fear of persecution.

'Since the military occupied the main square in Hama the protests have been organised in separate neighbourhoods,' he said.-Reuters