Syrian soldiers man a checkpoint in the city of Rastan in the central Homs province At least 20 civilians were killed by Syrian security forces on Friday as they pursued a crackdown against anti-regime protesters across the country, a rights group said.\"Eight civilians were killed in various neighbourhoods of Hama, 11 others in the city of Homs and one civilian was killed in Qusayr, in the region of Homs,\" the Syrian Observatory for Human Rights said, updating an earlier toll.
Hama and Homs are at the front line of the anti-regime protests that have rocked Syria since mid-March, since when UN estimates say more than 3,000 people, most of them civilians, have been killed in security crackdowns.
The army has been carrying out operations in Qusayr for several weeks, amid fighting there between troops and suspected army deserters, activists have said.
Clashes were also reported in Hama on Friday between suspected army defectors and members of the regular army and the security forces.
The latest bloodletting comes as activists called for nationwide protests on Friday to demand the imposition of a no-fly zone over Syria to protect civilians.
Syrian security forces opened fire, encircled mosques and carried out arrests on Friday in a bid to break up anti-regime protesters who are now calling for a no-fly zone in Syria to protect civilians, acrtivists said
At least four people were reported killed before and after midday prayers.
\"Despite the siege, the proliferation of checkpoints and the encirclement of mosques, people staged a mass demonstration in Kafr Nabl,\" a town in Idlib, near the border with Turkey, said the Syrian Observatory for Human Rights.
Demonstrators in the northwestern town marched \"in support of besieged cities\" and demanded \"the imposition of a no-fly zone,\" the Britain-based watchdog said, adding security forces also opened \"heavy fire\" and arrested \"five people\" there.
That call was echoed in the flashpoint central city of Homs, the focus of military raids in recent weeks, where demonstrators came out in \"most of the city\'s neighbourhoods,\" the Observatory said.
In the besieged neighbourhood of Bab al-Sebaa, one person was killed by sniper fire outside the mosque of Marjeh and another civilian was shot dead by a sniper in the same area while he was \"standing on his balcony\" at dawn, it added.
Meanwhile, activists said \"heavy gunfire\" and \"five explosions\" were heard in Qusayr, a restive town near the border with Lebanon, where security forces sought to break up demonstrators streaming out of several mosques.
\"Six people were wounded in Qusayr, two critically\" the Observatory said.
Bab al-Sebaa and Qusayr have both been focal points of deadly military sweeps.
In Hama, a city north of Homs, \"two people were killed and \"three others wounded\" by security forces who opened fire to disperse protest.
Three demonstrators were also arrested in the coastal city of Banias.
Troops also raided the northwestern town of Kafruma, arresting 13 people, including one woman and her 12-year-old son, the same source said.
In Maaret al-Numan, also in Idlib, the funeral of a soldier who defected and was shot dead on Thursday by security forces stationed at a checkpoint turned into a rally demanding the fall of Syrian President Bashar al-Assad\'s regime.
To the east, in Deir Ezzor, security forces opened fire against demonstrators as they streamed out of mosques after midday Friday prayers, which are a lightning rod for weekly anti-regime protests across the country.
Pro-democracy activist networks spurring protests on the ground each week adopt a new rallying call along the central demand for the fall of the regime.
This week they called for rallies in favour of \"a no-fly zone\" over Syria in order to protect civilians from military action and to encourage soldiers to defect.
That call coincided with the end of NATO\'s mission in Libya which had a mandate to protect civilians and ultimately tipped the scales in favour of regular citizens turned fighters who ousted ex-dictator Moamer Kadhafi.
\"We call on the international community to impose a no-fly zone so that the Syrian Free Army can function with greater freedom,\" said the Syrian Revolution 2011 on its Facebook page.
A defecting army officer who has taken refuge in Turkey, Colonel Riad al-Asaad, claimed in July to have established an opposition armed force called the \"Syrian Free Army\", but its strength and numbers are unknown.
On Thursday, China\'s special envoy for the Middle East Wu Sike reaffirmed his country\'s opposition to foreign interference in Syria, Syria\'s official news agency SANA said.
Wu, after holding talks in Damascus with Foreign Minister Walid Muallem, called for an \"end to all acts of violence... and to carry out reforms on the basis of dialogue and peaceful means.\"
Permanent UN Security council members Russia and China on October 4 vetoed a Western-proposed resolution threatening the Syrian leadership with \"targeted measures\" unless it halted the bloody repression.