Helicopter gunships backed by armoured vehicles are reported to have taken part in the attack on the town, know as a main hotbed of dissent against the Assad regime.
The Syrian Observatory for Human Rights has reported that after the killing of more than 150 people in the central village of Treimsa on Thursday, and despite the international outcry after this massacre, violence has persisted with reports indicating the government troops were also burning abandoned houses in Khirbet Ghazaleh. The Observatory added that a pregnant woman was among 19 people killed.
Referring to the UN Supervision Mission in Syria, Kofi Annan said that the use of artillery, tanks and helicopters, which has been confirmed by UNSMIS, is a violation of the Syrian government's obligations and commitment to cease the use of heavy weapons in population centres.
UN secretary general, Ban Ki-moon lashed out at the Syrian regime and called for the Security Council to urgently act to stop the bloodshed as its failure would give "a licence for further massacres.
In a letter to the Security Council, Mr Annan said: "Tragically, we now have another grim reminder that the council's resolutions continue to be flouted." He went on to call on the Security Council to "send a message to all that there will be consequences for non-compliance".
In a note to the council with Annan's letter, Mr Ban said: "I condemn this outrageous escalation of violence in the strongest possible terms, and fully concur with the views expressed by the joint special envoy,"
He called upon all member states to take collective and decisive action to immediately and fully stop the tragedy unfolding in Syria. ?Inaction becomes a licence for further massacres," he said.
On Twitter, he US ambassador to the United Nations, Susan Rice, said that the killings "dramatically illustrate the need for binding measures on Syria" by the council.
One of the rebel leaders by the name of Abu Mohammad, whose fighters are based near the Treimsa village, said more than 200 people were slaughtered on Thursday, according to AFP. However, the Observatory was more cautious, saying "several dozen rebel fighters were among those killed," adding that only around 40 of the dead had been identified, while 30 were burned and 18 were "summarily executed".
Observatory head Rami Abdel Rahman went on to tell AFP, it "might be the biggest massacre committed in Syria since the start of the revolution."
The news agency also quoted a spokesman for Syria's military saying that the army killed "many terrorists" in Treimsa, but no civilians, in a "special operation... targeting armed terrorist groups and their leadership hide-outs."