The opposition Syrian National Council called on Monday for an "urgent" foreign military intervention in Syria after reports that 47 women and children were killed in a Homs "massacre."
"We request urgent Arab and international military intervention," top SNC leader Georges Sabra told a news conference in Istanbul.
Reading from a prepared text, he also called for the creation of a "no-fly zone" over all of Syria and "strikes" against the Syrian armed forces.
He urged "the friends of the Syrian people to take a steadfast position" on the bloodshed and said the regime responded to a weekend mission by international peace envoy Kofi Annan "with violence and killings."
SNC chief Burhan Ghalioun said the "international community can no longer make hollow promises and the Arab League cannot go on publishing press releases if they want to end the deadly violence.
"It is time for the international community to take serious and concrete measures to end the violence," said Ghalioun.
The bodies of 47 women and children, some with their throats slit, were found in Homs after a "massacre" that sent families fleeing the flashpoint central city, activists and the opposition said earlier on Monday.
Earlier, activists had posted videos online that showed graphic images of charred bodies and children with mutilated and bloodied faces.
Syria's state television also aired gruesome footage showing homes with white walls splattered with blood, bodies of women and children piled on top of each other and several men, with bullet wounds to the head, lying facing down in a disused building, their hands tied behind their backs.
"More massacres could take place if the international community fails to act," Hadi Abdallah, a Syrian activist in Homs, told AFP. "We urge a military intervention, strikes against the regime and arming the rebel Free Syrian Army.
"Enough with words. The United States and others for months have been calling on the (regime) to stop the violence, but it continues to kill people."
The SNC had called for an emergency UN Security Council meeting to discuss the "massacre", which it said took place on Sunday.
"The Syrian National Council is making the necessary contacts with all organisations and countries that are friends with the Syrian people for the UN Security Council to hold an emergency meeting," the SNC had said in a statement.