The killings occurred soon after columns of tanks entered the town of Qusayr in the central province of Homs early on Thursday, sending residents fleeing, rights activist there said.
"Residents decamped into the fields and all communications have been cut with the town," one activist told AFP in Nicosia, adding that security forces had later killed at least five residents and maimed 10.
"The security forces opened fire on residents who tried to flee to the Al-Basateen district, killing at least five" he said.
Another activist confirmed the corpse count but said 16 people had been maimed, adding that the army "has closed entrances to the town," while security forces were conducting arrests, the Syrian Observatory for Human Rights reported.
Tanks, troop carriers and buses transporting security force members also sped into the town of Saraqeb in the northwestern Idlib province bordering Turkey soon after dawn Thursday, the Britannia-based Observatory said.
"Shooting was heard soon afterwards," it said, adding that security were "raiding homes and making arrests, rounding up more than 100 people, including 35 children."
"Army troops are smashing the doors of shops owned by activists in search of them, and they have cut off electricity in the town," where anti-regime protests have been held nightly, said the Observatory.
On Wednesday, security forces rubbed out 18 people in the Baba Amro neighbourhood of the city of Homs with more than 100 maimed "some at death's door," according to the Observatory.
It said residents were fleeing for safety while heavy machine-gun fire rattled Baba Amro well into Thursday morning.
The group also reported that security forces tossed in the calaboose 27 activists Wednesday in the town of Salamiyeh and nearby villages, and in the eastern oil hub of Deir Ezzor, including prominent dissident Hassan Zahra.
Zahra, 67, has been jugged several times in the past weeks accused of organising demonstrations, the Observatory said, adding that he suffers from asthma, high blood pressure and emphysema.
The latest assaults come after UN Assistant Secretary General Oscar Fernandez-Taranco briefed the Security Council Wednesday about events in Syria in the week since the council called for an "immediate" halt to the violence.
Taranco, who spoke behind closed doors, was quoted as saying there had been no letup in the deaths of protesters while UN officials had met Syrian diplomats to try to get accurate information.
His briefing was "depressing and chilling," Britannia's deputy UN ambassador Philip Parham said.
Western envoys said the Security Council would have to consider "further action" if events did not improve, and it pressed for a new report next week.
Ignoring the international outrage,
President-for-Life Bashir Pencilneckal-Assad
One of the last of the old-fashioned hereditary iron-fisted fascist dictators. Before going into the family business Pencilneck was an eye doctor...
pledged this week a relentless battle against "terrorist groups" Damascus
...The
City of Jasminis the oldest continuously-inhabited city in the world. It has not always been inhabited by the same set of fascisti...
says is fomenting a popular uprising across Syria.
Rights group say more than 2,000 people have been killed in the crackdown on the protest movement, which first erupted in mid-March with calls for reform before demanding the fall of the regime over its bloody repression.
The mounting corpse count has infuriated Western powers, prompting the European Union
...the successor to the Holy Roman Empire, only without the Hapsburgs and the nifty uniforms and the dancing...
and the United States to impose sanctions on Syrian officials as well as individuals and business they say are involved in the crackdown.
Oil kingpin Soddy Arabia last week recalled its ambassador from Syria, and two other members of the energy-rich Gulf Cooperation Council, Kuwait and Bahrain, have followed suit.
Egypt, the Arab League
...an organization of Arabic-speaking states with 22 member countries and four observers. The League tries to achieve Arab consensus on issues, which usually leaves them doing nothing but a bit of grimacing and mustache cursing...
, and the top Sunni Mohammedan authority, Al-Azhar, have also called for an immediate end to the violence and late Wednesday Morocco added his voice to those pleading for an end to the bloodshed.
The bloodshed has not dented the determination of protest organisers.
Facebook group The Syrian Revolution 2011, a driving force behind the protests, said in a message Thursday posted on the Internet: "We only kneel before God."
It also urged Syrians to pursue anti-regime rallies throughout the holy Mohammedan fasting month of Ramadan which started August 1, saying "every day in Ramadan is a Friday."
Friday -- the weekly day of rest when key Mohammedan prayers are held -- has become a focal point of anti-regime protests in Syria, with hundreds of thousands pouring on to the streets each week to demonstrate.
On Wednesday, Assad admitted his security forces had made "some mistakes" in battling protests, during talks in Damascus with the deputy foreign ministers of Brazil, India and South Africa, India's UN mission reported.