Story highlights 37 people are killed throughout Syria on Sunday, an opposition group says

Syrian president: "Even monsters do not do what we saw" in Houla

Opposition: Five people are killed as shelling fell on cities during al-Assad's speech

Kofi Annan: The specter of all-out civil war with a sectarian dimension grows every day

Syrian President Bashar al-Assad denied Sunday that government forces were behind the "outrageous" massacre of more than 100 civilians, including dozens of small children, in the town of Houla.

"Truthfully, even monsters do not do what we saw, especially in the Houla massacre," he told lawmakers. "The criminal or criminals who committed this crime and others are not criminals for an hour or criminals for a day, they are constant criminals and are surely planning other crimes."

Speaking before the newly-elected People's Assembly on Sunday, al-Assad decried what he called the "terrorists" and "conspiracy" against Syria.

"At this time, we are facing a war from abroad," al-Assad said in his first public speech since January. "Dealing with it is different from dealing with people from inside."

His speech came a week after the U.N. Security Council condemned the Houla massacre, with members casting blame on government forces for the deaths.

Photos: Photos: Massacre in Syria Photos: Photos: Massacre in Syria Hide Caption 1 of 7 Photos: Photos: Massacre in Syria Massacre in Syria – Syrians surround a U.N observer vehicle after placing the bodies of a girl and man on the car in Houla on Saturday, May 26, 2012. The photo is from the opposition Shaam News Network. Forty-nine children were among the 108 slaughtered in Houla on Friday, May 25, U.N. monitors say. The massacre in Houla, a suburb of the anti-government bastion of Homs, has reignited international fury against Bashar al-Assad's regime. Hide Caption 2 of 7 Photos: Photos: Massacre in Syria Massacre in Syria – The body of a slain Syrian child lies next to other shrouded bodies at a hospital mortuary in Houla on Saturday in another photo from the opposition Shaam News Network. Al-Assad's regime insists it is not behind the massacre and blames terrorist groups. Syria has attributed violence on "armed terrorist groups" throughout the 14-month-old uprising. Hide Caption 3 of 7 Photos: Photos: Massacre in Syria Massacre in Syria – Bodies of children lie in a Houla hospital morgue before their burial Saturday in another photo from Shaam News Network. Images from the town show a room crammed with mangled and bloody bodies of children -- some with their skulls torn open. Hide Caption 4 of 7 Photos: Photos: Massacre in Syria Massacre in Syria – U.N. observers visit a hospital morgue in Houla on Saturday before the burial of massacre victims. Opposition activists and residents blame al-Assad's regime for the bloodbath. Hide Caption 5 of 7 Photos: Photos: Massacre in Syria Massacre in Syria – A Houla resident shows a body to a U.N. observer at a mosque in the central Syrian town. Some U.N. Security Council members condemned the attacks "that involved a series of government artillery and tank shellings on a residential neighborhood" as well as killings of civilians by close-range gunshots. Hide Caption 6 of 7 Photos: Photos: Massacre in Syria Massacre in Syria – Syrians gather at a mass burial Saturday in Houla. "Those responsible for these brutal crimes must be held accountable," Kofi Annan, the U.N.-Arab League special envoy, said in a statement. Hide Caption 7 of 7

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Al-Assad's remarks stand in stark contrast to what the opposition and many world leaders have said for more than a year -- that al-Assad's forces, not "terrorists," are behind a sustained slaughter stemming from the regime's crackdown on dissidents.

As the president spoke, heavy shelling rained on the anti-government bastion of Homs, the opposition Local Coordination Committees of Syria said. Thirty-seven people were killed throughout Syria on Sunday, including five children, the group said.

Opposition activists also reported seeing a large military convoy of about 45 trucks carrying tanks, armored personnel carriers and soldiers heading toward Deir Ezzor during al-Assad's speech.

Al-Assad insisted "the battle is forced upon us," but promised amnesty for those who stop fighting immediately.

"I encourage all of those who are hesitant to drop their weapons at once, and the government will not seek revenge now or later," he said in his 70-minute speech. "We forgave others who stood against us in the past."

The president also touted what he called political reforms and denounced those he said were conspiring against Syria.

"Standing up against the conspiracy is not easy, but we will overcome the obstacles," al-Assad said.

The president's address came a day after U.N. special envoy Kofi Annan said Syria is "at a turning point" and that "the specter of all-out civil war, with a worrying sectarian dimension, grows by the day."

Saudi Foreign Minister Saud Al Faisal said the Syrian regime is pushing for a sectarian crisis.

"The Syrian opposition lacks the means to defend itself, and the regime is getting weapons from everywhere. For a while now, we noticed that the regime has been trying to turn the crisis into a sectarian conflict," Al Faisal said Sunday.

He added that while Syria had agreed to Annan's peace plan, the regime has not implemented it. "The regime just wants to buy time," Al Faisal said.

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Catherine Ashton, the EU foreign policy chief, said no efforts should be spared to stop the violence.

"We need to avoid a catastrophe. Violence and repression cannot be the solution. Any further militarization of the conflict will bring enormous suffering to Syria and risks having a dramatic impact on the region," she said.

As Annan's U.N.-backed peace plan continued to founder in Syria, Arab leaders signaled the need for more robust measures to end the violence there.

At a meeting in Doha, Qatar, more than a week after the Houla massacre sparked global outrage, Arab League Secretary-General Nabil el-Araby said " more audacious steps are needed " in Syria.

"We should have a timeline for the peace plan -- this is a must," el-Araby said. "The international community needs to take immediate action after the massacre in Houla and take all necessary measures in order to protect the Syrian civilians."

Qatari Prime Minister Sheikh Hamad bin Jassim bin Jabor Al Thani said Annan's peace initiative should be placed under Chapter VII of the U.N. charter, Qatar's news agency reported. Such a move would allow the U.N. Security Council to take action that could include the use of military force.

U.N. Secretary-General Ban Ki-moon said Sunday that he had taken note of the Arab League leaders' suggestions, including requests to increase the number of U.N. observers and to set a time limit for the effort.

"All these are very important recommendations and I hope these will be discussed by the Security Council members. At this time, I would welcome the wider international discussions on the future course of action," he told reporters.

The crisis in Syria began nearly 15 months ago, when a tough government crackdown on protesters spiraled out of control and spawned a national anti-government uprising. The United Nations for months has said more than 9,000 people have died in Syria. But death counts from opposition groups range from more than 12,000 to more than 14,000. Tens of thousands have been displaced.

The opposition Syrian Observatory for Human Rights said 33 civilians and 61 government forces were killed across Syria on Saturday, and two rebel soldiers died.

CNN cannot independently confirm reports of casualties or violence from Syria because the government restricts access to foreign journalists.

Over the border in the Lebanese city of Tripoli, fighting between pro- and anti-Syrian regime gunmen on Saturday left 12 dead and approximately 50 injured , according to the state-run National News Agency.

The clashes continued early Sunday morning, killing at least one person, NNA said. But hours later, residents said the situation in Tripoli was quiet.

The sectarian violence in Tripoli mirrors the tensions in Syria between Sunnis, who make up the majority of the Syrian opposition, and Alawites, who are dominant in al-Assad's government.

Annan made reference Saturday to such flare-ups in neighboring countries, after many Syrian civilians have fled to escape violence.