Helicopter gunships backed by armoured vehicles took part in the attack on Khirbet Ghazaleh in the southern province of Daraa on Saturday, a main hotbed of dissent against the Assad regime, said the Syrian Observatory for Human Rights.
An activist on the ground who identified himself as Bayan Ahmad gave a similar account, saying troops were burning abandoned houses in Khirbet Ghazaleh.
Elsewhere, a pregnant woman was among 19 people killed, the Observatory said, a day after 118 people died including dozens of civilians troops gunned down at anti-regime protests across Syria.
The violence persisted despite an international outcry over the killing of more than 150 people in the central village of Treimsa on Thursday.
Ban, the UN secretary general, 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."
"I call 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.
The Treimsa killings have added urgency to deadlocked Security Council negotiations on a Syria resolution.
The US ambassador to the United Nations, Susan Rice, said on Twitter that the killings "dramatically illustrate the need for binding measures on Syria" by the council. "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," peace envoy Kofi Annan said, referring to the UN Supervision Mission in Syria.
"Tragically, we now have another grim reminder that the council's resolutions continue to be flouted," he said in a letter to the 15-nation council. He again called on the Security Council to "send a message to all that there will be consequences for non-compliance".
"I condemn this outrageous escalation of violence in the strongest possible terms, and fully concur with the views expressed by the joint special envoy," Ban said in a note to the council with Annan's letter.
Western nations have proposed a resolution that would impose sanctions on Assad over the conflict, which rights activists say has cost more than 17,000 lives.
Britain, France, the United States, Germany and Portugal have proposed a resolution that would give Assad 10 days to stop the use of heavy weapons, in line with the Annan plan, or face sanctions. They only want to give the UN observer mission a new 45-day mandate.
Russia has rejected any use of sanctions and is proposing a rival resolution that renews the mandate of UNSMIS, which ends on July 20, for 90 days and has said sanctions are unacceptable.
French President Francois Hollande called on Russia and China not to oppose sanctions, saying it would "only result in chaos and war in Syria at the expense of (your) own interests."
Iran said it is ready to play an "appropriate role in bringing stability and security in Syria" to prevent the crisis "quickly spreading to the whole region," foreign ministry spokesman Ramin Mehmanparast told the Iran newspaper.
Rebel leader Abu Mohamad, whose fighters are based near the Treimsa village, said more than 200 people were slaughtered on Thursday.
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 told AFP it "might be the biggest massacre committed in Syria since the start of the revolution."
If confirmed, the 150-person toll would exceed that of a massacre at Houla on May 25, when a pro-Assad militia and government forces were accused of killing at least 108 people.
A spokesman for Syria's military said the army killed "many terrorists" in Treimsa, but no civilians, in a "special operation... targeting armed terrorist groups and their leadership hide-outs."
Treimsa, which had a population of 7,000, "is empty now. Everyone is dead or has run away," an activist calling himself Abu Ghazi said. Treimsa is near Al-Kubeir, where at least 55 people were killed on July 6, according to the Observatory. Like Al-Kubeir, Treimsa is a majority Sunni village situated near Alawite hamlets.
Assad belongs to the Alawite community -- an offshoot of Shiite Islam -- although most Syrians are Sunni.