JEFFREY BROWN: A new wave of international criticism followed the news of more horrific violence in Syria. That came as U.N. observers on the ground were fired upon as they tried to access the site of the latest mass killing.
Ray Suarez has the story.
RAY SUAREZ: Amateur video showed what's believed to be the aftermath of shelling in the central province of Hama, at a small farming town called Mazraat al-Qubair. The faces of the victims have been blurred.
After a six-hour artillery assault, opposition activists say government-backed militias entered the town and executed men, women and children, leaving at least 78 dead.
Speaking today in Turkey, Secretary of State Hillary Clinton renewed her call for Syrian President Bashar al-Assad to step aside.
SECRETARY OF STATE HILLARY RODHAM CLINTON: The regime-sponsored violence that we witnessed again in Hama yesterday is simply unconscionable. Assad has doubled down on his brutality and duplicity, and Syria will not, cannot be peaceful, stable or certainly democratic until Assad goes.
RAY SUAREZ: This latest atrocity comes less than two weeks after the slaughter 30 miles south in Houla; 108 died there. Those killings led to international condemnation and the coordinated expulsion of Syrian diplomats from the U.S. and countries around the world.
The Syrian government, however, has denied responsibility for either incident and maintains that armed rebel groups and terrorists are to blame. At the U.N.'s General Assembly in New York, Secretary-General Ban Ki-Moon described the acts in Hama and Houla as unspeakable barbarity. And he said U.N. observers there as part of an eight-week-old cease-fire agreement were in immediate danger today.
BAN KI-MOON, United Nations secretary-general: They are working now to get to the scene, and I just learned a few minutes ago that, while trying to do so, the U.N. monitors were shot at with small-arms.
RAY SUAREZ: Special envoy Kofi Annan, former U.N. secretary-general, met with President Assad just days after the Houla massacre and had strong words for the regime.
KOFI ANNAN, former U.N. secretary-general: President Assad believed that the main obstacle was the actions of militants. Clearly, all parties must cease violence, but equally clear, the first responsibility lies with the government.
RAY SUAREZ: Annan warned that the time to implement his peace plan is rapidly dwindling.
KOFI ANNAN: If things do not change, the future is likely to be one of brutal repression, massacres, sectarian violence and even all-out civil war. All Syrians will lose.
RAY SUAREZ: For his part, Syria's ambassador to the United Nations questioned the U.N.'s account of events.
BASHAR JA'AFARI, Syrian ambassador to the United Nations (through translator): What's occurring in certain parts of my country is truly an atrocious massacre. It is unjustifiable. The analysis is based on media and political work which doesn't relate to what's occurring on the ground.
RAY SUAREZ: Russia and China, permanent members of the Security Council, have backed the Syrian government's version of events and called for more time to allow Annan's peace plan to work.
But, in Washington, Arizona Republican John McCain, the ranking member of the Senate Armed Services Committee, said it's time to use force.
SEN. JOHN MCCAIN, R-Ariz.: How many more have to die, how many more have to die, how many more young women have to be raped, how many young -- more young Syrians are going to be tortured and killed, how many more, how many more before we will act?