Syria's army stormed another two towns on Thursday in pursuit of anti-regime protesters, activists said, in defiance of Western calls for action after a "chilling" UN Security Council briefing.
Tanks, troop carriers and buses transporting security force members sped soon after dawn into the town of Saraqeb in the northwestern Idlib province bordering Turkey, the Syrian Observatory for Human Rights said.
"Shooting was heard soon afterwards in the town, where protests demanding the fall of the regime have been staged every day after the evening (Muslim) prayers," the statement said.
Later the rights advocacy group reported that security forces were "raiding homes and carrying out 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," a statement said.
Further south, in the central province of Homs, columns of tanks entered Qusayr early on Thursday, a rights activist in the town said, reached by telephone.
"Residents fled into the fields and all communications have been cut with the town," the activist said.
The operations came a day after security forces reportedly shot dead 18 people in the Baba Amro neighbourhood of the city of Homs, according to the latest toll provided by the Syrian Observatory.
"The number of those wounded has risen to over 100, some of them in critical condition, and residents from Baba Amro have begun to flee looking for safer places in the city," a statement said.
It said heavy machine gun fire rattled Baba Amro well into Thursday morning.
The latest assault comes after UN Assistant Secretary-General Oscar Fernandez-Taranco on Wednesday briefed the 15-member Security Council 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.
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Taranco's briefing had been "depressing and chilling," Britain's deputy UN ambassador Philip Parham later told reporters.
Western envoys said the Security Council would have to consider "further action" if events did not improve and pressed for a new report next week.
Ignoring the international outrage, President Bashar al-Assad this week pledged a relentless battle against "terrorist groups" Damascus 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 death toll has infuriated Western powers, prompting the European Union 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 Saudi 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, and the top Sunni Muslim 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 Muslim fasting month of Ramadan which started August 1, saying "every day in Ramadan is a Friday."
Friday -- the weekly day of rest when key Muslim 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 reportedly 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.
Assad "acknowledged that some mistakes had been made by the security forces in the initial stages of the unrest and that efforts were under way to prevent their recurrence," said the statement released by India's UN mission.