Prime Minister David Cameron has condemned reports of a "brutal and sickening" massacre of civilians in Syria and called for "concerted action" from the international community against the regime of President Bashar al-Assad.
Speaking during a visit to Norway, Cameron said the massacre of at least 86 people, many of them women and children, was further proof that the Assad regime was "completely illegitimate and cannot stand".
Activists have blamed pro-government militia and security forces for the deaths in the farming villages of Qubair and Maarzaf, 12 miles north of Hama. Horrific reports have emerged from activists close to the scene including one of a three-month old baby burned to death and others of men being stabbed outside their homes
Describing the attack, activists from the Syrian Network for Human Rights said that tanks rolled in "levelling half the houses". Pro-government forces then opened fire randomly on the residents of the villages, leading the men outside and "slaughtering many of them by knives".
Many of the victims were burned after being stabbed, claims the joint report by SNHR and Damascus Centre for Human Rights Studies.
The pro-government militia wanted to "obscure evidence of the crime," avoiding the international outrage provoked by the Houla massacre earlier in May, activists report, claiming 37 bodies were also abducted.
There are also reports that some of the victims were shot at close range. One activist told the BBC's World Tonight that he had seen the body of a three-month-old baby "burned to death."
"One of the most painful scenes is the burned bodies [showing] a woman embracing her two children all of whom were burned to death due to shelling" report activists.
The SNHR claim that only a few remaining villagers managed to escape. There are unconfirmed reports that more than 100 people were killed, according to Sky News, which would make the massacre some of the worst bloodshed in the 15 month uprising. UN monitors are currently on their way to the village to confirm the deaths, reports the BBC.
Both Quabiar and Maarzaf are small villages, with a CNN correspondant tweeting that more than 70 people have died in Quabiar, which already had a tiny population of 150.
Syrian state TV said troops found some bodies after attacking "terrorists".
A statement on Syrian state TV reported by AFP added: "The reports by the media are contributing to spilling the blood of Syrians."
Cameron said: "If these reports are true, it is yet another absolutely brutal and sickening attack.
"Frankly, the international community has got to condemn absolutely this regime and President Assad for what he is doing.
"I think that lots of different countries in the world - countries that sit around the UN Security Council table - have got to sit down today and discuss this issue.
He called on the international community to "do much more" to "isolate Syria, to isolate the regime, to put the pressure on and to demonstrate that the whole world wants to see a political transition from this illegitimate regime and to actually see one that can take care of its people.
"It really is appalling, what is happening in that country, and I want to see concerted action from the international community."
His words convey a clear message to Russia and China, which have blocked international action against Assad. At a meeting of the UN Security Council in New York on Thursday UN-Arab League envoy Kofi Annan is expected to propose a contact group to try and revive his ailing peace plan, which was meant to see a ceasefire between opposition groups and Assad's regime in April. The council would include international and regional powers, including Russia and China which would then negotiate with the government in Damascus.
The massacre in the villages outside Hama follow some of the the worst bloodshed since the start of the U.N peace plan. An attack on Houla, in central Syria, resulted in the deaths of more than 90 people, including 32 children under the age of 10, according to United Nations observers, earlier in May.
Local activist Abu Yazan told the paper that the shelling killed 12 people, with 106 killed by pro-regime thugs called "shabiha".
Videos posted to an activist network appear to show the killings in Hama, but they have not been independently verified. The content is too graphic to embed in this article.