BEIRUT // An attack on a village in the Hama region, where more than 200 people have been reported killed, was an extension of a Syrian air force operation, UN observers said in a report yesterday.
The UN mission said in a report obtained by Reuters that Thursday's massacre showed "the situation in Hama province continues to be highly volatile and unpredictable".
It said the Syrian Arab Air Force (SAAF) continued "to target populated urban areas north of Hama City in a large scale".
Syrian opposition groups called for tougher action from the international community after reports of the massacre in Tremseh, a farming village.
The killing continued across the country yesterday, with opposition groups saying at least 75 people died.
Reports said that early on Thursday, Syrian military forces surrounded Tremseh, the mainly Sunni village west of the city of Hama, before bombarding the area with artillery, tank shells, and missiles fired from at least one helicopter.
After the shelling, government forces and pro-regime militia, known as shabbiha, moved in and killed more people, activists said.
There were also reports that members of the Free Syrian Army tried to fend off the attacks and rebel fighters were among the dead.
The accounts could not be independently confirmed but if true, the killings in Tremseh would represent one of the worst single days of bloodshed since the uprising against the regime of the Syrian president, Bashar Al Assad, began 16 months ago.
The head of the six-nation Gulf Cooperation Council called for the UN Security Council to take firm action against Damascus after the mass killings.
Abdellatif Zayani branded Thursday’s killings “a savage, terrorist act contrary to the precepts of Islam” and urged the Security Council “to put an end to the painful tragedy of the Syrian people".
Hillary Clinton, the US secretary of state, expressed outrage over reports of the massacre and urged the Security Council to make clear to Damascus that there would be consequences.
"We call for an immediate ceasefire in and around Hama to allow the UN observer mission to enter Tremseh," Mrs Clinton said. "Those who committed these atrocities will be identified and held accountable."
The UN report said a patrol of unarmed UN military observers could only get within six kilometres of Tremseh and were stopped by SAAF commanders because of "military operations".
The UN patrol observed the situation from a few locations around Tremseh for about eight hours, during which time it heard more than 100 explosions, sporadic small arms and heavy machinegun fire and saw smoke.
It saw an Mi-8 and two Mi-24 helicopters, one of which fired rockets.
"The patrol received several calls from local contacts claiming 50 people had been killed and 150 wounded within Tremseh," the report said.
"Attempts to contact the local military commander during this period were unsuccessful," it said. "Patrols attempted to access Tremseh via alternate routes without success."
The report said attempts to get a local ceasefire so civilians could be evacuated from Tremseh were made by contacting the Hama governorate chief of police and the SAAF senior national liaison officer, but did not succeed.
"Such massacres will continue in Syria if the international community does not stop the killer," said Abdulbaset Saida, the chairman of the Syrian National Council (SNC), the main opposition group.
Mr Saida said the Syrian government was treating efforts made by the UN-Arab League envoy to Syria, Kofi Annan, to revive his peace plan "as a new chance to continue the killings".
He called on the UN Security Council to agree on a resolution allowing steps against the Syrian government under Chapter Seven of the UN Charter, which can authorise foreign powers to take measures including the use of military force.
"It should include every possibility, including the use of military power," Mr Saida said.
Condemnation for the killings was swift yesterday, with Mr Annan saying he was "shocked and appalled" by reports of the attack.
"Tragically, we now have another grim reminder that the Council's resolutions continue to be flouted," he said in a letter, noting that on Wednesday he had urged the Security Council to send a message that there would be consequences for non-compliance.
"This is imperative and could not be more urgent in light of unfolding events."
The Syrian government yesterday referred to the killings in Tremseh, saying more than 50 people had been killed by "armed terrorist groups" - the term it uses to refer to regime opponents.
Sana, the state news agency, reported eye witnesses as saying that "terrorists … ransacked, destroyed and burned scores of the village houses" before security forces moved in.
Video footage posted online late on Thursday and purported to be from Tremseh showed the corpses of 15 men lined on a floor. Some are covered in blood, with wounds to their heads and chests.
One video showed a young man wailing over the body of an elderly man wrapped in a blanket and lying in the street.
"Come on, Dad. For the sake of God, get up," the man sobs. A boom is heard in the background.
The UK-based Syrian Observatory for Human Rights yesterday said more than 160 people had been killed in Hama province on Thursday, most in Tremseh. The group also reported that rebel fighters were among the dead and lists of names of the deceased were still being compiled.
The Local Coordination Committees (LCC), another opposition group, said as many as 220 people had been killed there.
The network of activists called on the international community to protect the lives of Syrian civilians and said the attack mirrored previous mass killings.
Amnesty International yesterday said reports of the mass killings were further proof of the need for UN monitors to be granted full and immediate access throughout Syria to carry out independent investigations into rights abuses.
The French foreign ministry spokesman Bernard Valero said Paris the tragedy proved that the Syrian government must take the "first step towards a cessation of violence".
Lebanon's former prime minister, Saad Hariri, also condemned the killings and called on the international community to take "practical, decisive and immediate measures" to protect the Syrian people.
* Additional reporting by Thomas Seibert in Istanbul, Associated Press, Reuters and Agence France-Presse