AMMAN, Oct 28 (Reuters) - Syrian government forces killed at least 20 civilians when they opened fire at demonstrations that started after Friday prayers in Hama and Homs 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, a city of one million, 140 km (85 miles) north of Damascus, 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.
Hama, scene the massacre of thousands by the military in the 1980s that was the bloodiest in modern Syrian history, came under attack by government forces at the beginning of the fasting month of Ramadan in August to end pro-democracy rallies.
The authorities said "armed terrorist gangs" were operating in Hama, killing army and police and "frightening inhabitants yearning for peace and security".
In Damascus, Youtube footage sowed a crowed of hundreds holding shoulders and swaying in a traditional 'dabka' dance while singing an adaption of an old ballade.
"Tears flows from the eye, my mother, crying for Syria's youth," they chanted.
International outrage has mount as the civilian toll rose in Syria. The United Nations is conducting an investigation into what it says are possible human rights violations, but world powers show no sign of repeating action similar to Libya.
Assad held an inconclusive meeting on Wednesday with Arab ministers seeking to end the bloodshed by mediating a dialogue between him and his opponents.
The Arab League had called on the two sides to agree to a dialogue within two weeks.
The authorities said they had reservations about the proposal while opposition figures said they cannot sit down with them if killings of protesters, disappearances and mass arrests do not stop.
Reporting by Khaled Yacoub Oweis, Amman newsroom; Editing by Angus MacSwan