The Syrian president, Bashar al-Assad, has said his government had nothing to do with the Houla massacre, saying not even "monsters" would carry out such an ugly crime.
The speech on Sunday were Assad's first comments on the killings. As in other speeches, he insisted terrorists were behind the country's uprising.
A massacre last week in Syria's central region of Houla killed more than 100 people, nearly half of them children.
The opposition and the government have exchanged accusations over the massacre, each blaming the other. UN investigators have said there are strong suspicions that pro-regime gunmen were responsible for at least some of the killings.
Assad said his country was facing a "real war," warning that he would not be lenient with the terrorists he blamed for the country's uprising.
"We have to fight terrorism for the country to heal," Assad told parliament in his first speech since January. "We will not be lenient. We will be forgiving only for those who renounce terrorism."
Assad's remarks defied mounting international condemnation of his regime's crackdown on the opposition. He blamed the crisis on outside forces and said the country was passing through its most critical stage since the end of colonialism.
His message was similar to his previous speeches, when he blamed terrorists and foreign extremists for the uprising and vowed to protect national security. The revolt began in March 2011 with mostly peaceful protests, but a ferocious government crackdown led many in the opposition to take up arms. Now, the conflict has turned into an armed insurgency.
"A battle was forced on us, and the result was this bloodshed that we are seeing," Assad said.
Activists say as many as 13,000 people have died in the violence. One year after the revolt began, the UN put the toll at 9,000, but hundreds more have died since.
Syria has long faced international isolation, but the Houla massacre has brought a new urgency to calls to end the crisis. A ceasefire plan brokered by international envoy Kofi Annan is violated by both sides every day. Fears have also risen that the violence could spread and provoke a regional conflagration.
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