(CNN) -- Accusations that government troops were involved in the massacre of more than 100 civilians, including dozens of small children, in the Syrian town of Houla are "baseless," President Bashar al-Assad told lawmakers Sunday.

"Monsters don't commit what we have seen in Houla," he said. "The criminals who committed these massacres were not criminals for an hour or a day, they were criminals by nature, so we need to prepare ourselves and defend our people."

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.

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. At the same time, at least five people were killed in Homs, Aleppo and Hama, 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.

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.

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.

He said he recently urged al-Assad "to radically change his military posture," saying the government has the prime responsibility to halt the violence.

Annan said he plans to brief the U.N. General Assembly and U.N. Security Council about the crisis this week.

CNN's Saad Abedine, Holly Yan and Hamdi Alkhshali contributed to this report.