Damascus: Syrian troops backed by tanks rolled into the flashpoint town of Daraa on Monday, killing at least 25 people, witnesses said, as Damascus was accused of choosing the military option to crush dissent.
The Syrian army however, insisted it had been invited into the southern town at the request of citizens to hunt "extremist terrorist groups."
Witnesses said troops also launched assaults on the Damascus suburbs of Douma and Al-Maadamiyeh, as a leading Syrian rights activist accused the regime of going for the "military solution" to end six weeks of dissent.
The United States, which has repeatedly condemned Syria`s repression, was considering sanctions against Damascus.
"The United States is pursuing a range of possible policy options, including targeted sanctions, to respond to the crackdown and make clear that this behaviour is unacceptable," said National Security Council spokesman Tommy Vietor.
Monday`s assault began at dawn with 3,000 to 5,000 army and security forces swooping on Daraa, with tanks taking up position in the town centre and snipers deploying on rooftops, activists said.
The operation came less than a week after President Bashar al-Assad signed a decree to abolish nearly five decades of draconian emergency rule in a bid to placate protesters demanding political reform and the fall of the regime.
Activist Abdullah Abazid told AFP Syrian forces pounded Daraa with heavy artillery and that "at least 25 martyrs have fallen."
"There are still bodies sprawled in the streets," he said by telephone, with the sound of loud explosions and gunfire in the background.
A group of activists said in a statement "more than 25 people fell but no one could reach them because of the heavy shelling" and that only seven bodies were retrieved, including a father and his two sons.
The army disputed these reports, with a military official saying the troops entered Daraa "in response to calls for help from" citizens to rid them of "extremist terrorist groups" behind a spate of killings and sabotage.
The official, quoted on state television, said troops backed by security forces clashed with gunmen and the confrontations led to "a number of martyrs in the ranks of the army and the security forces."
Activists said troops fired anti-aircraft guns and seized at least two mosques as well as the cemetery where scores of people killed in anti-regime protests are buried.
"The minarets of the mosques are appealing for help. The security forces are entering houses. There is a curfew and they fire on those who leave their homes. They even shot at water tanks on roofs to deprive people of water," said a witness.
A huge crackdown was also reported in Douma, a large suburb in northern Damascus, and nearby Al-Maadamiyeh, said activists and residents reached by telephone.
"The situation is dramatic. Patrols man each alleyway and prevent people from going out even to buy bread," one resident said.
Security forces "surrounded a mosque and are firing indiscriminately. Streets are cut off from each other and Douma is isolated from the outside world," an activist said.
Some 390 people have been killed in security crackdowns since the protests erupted, rights activists and witnesses say.
Assad signed decrees on Thursday scrapping repressive emergency rule, abolishing the state security court that has tried scores of regime opponents, and one to "regulate" protests.
A day later, tens of thousands of people swarmed cities and towns to test the government`s sincerity, but scores were killed by security forces, activists and rights groups have said.
Prominent rights activist Rami Abdel Rahman told AFP that Monday`s crackdown showed Damascus had decided to crush the protests militarily.
"It is clear that the Syrian authorities have taken a decision for a military and security solution," said Abdel Rahman, who heads the London-based Syrian Observatory for Human Rights.
UN High Commissioner for Human Rights Navi Pillay denounced the killings from Geneva saying "we are seeing such disregard for human life by Syrian security forces."
So far, Washington has not threatened to recall its ambassador to Syria, a post filled in January after a six-year absence, as President Barack Obama sought to court Damascus as part of a broader Middle East diplomatic push.
"Having an ambassador in Syria has allowed us to be in Syria, basically, in the presence of the government to make our views known directly and not be a long distance (away)," White House spokesman Jay Carney said.
Britain, France, Germany and Portugal were meanwhile seeking a UN Security Council condemnation of the violence and an independent probe into the killings.