BEIRUT - French President Nicolas Sarkozy said the Syrian regime is committing massacres and he is calling on President Bashar Assad to leave power.

Sarkozy's comments came during a New Year's address at a Navy airbase in Lanveoc-Poulmic, France.

He said the "massacres being committed by the Syrian regime" have aroused disgust around the world and that Assad should allow Syrians to decide their own future.

"The Syrian president must leave power," he told members of the French military.

Syria unleashed a military assault to crush a 9-month-old uprising in which, according to United Nations estimates, 5,000 people have been killed.

An Arab foreign ministers' committee on Syria will meet on Saturday to discuss a preliminary report from monitors sent to the country to observe compliance with a peace plan, Arab League sources said on Tuesday.

The monitors have spent the past week assessing President Assad's response to the plan, brokered by the Arab League, to end the violence.

The meeting will bring together Arab League Secretary General Nabil Elaraby and the foreign ministers of Egypt, Sudan, Algeria, Qatar and Oman, the sources said.

Meanwhile an explosion struck a gas pipeline in central Syria in an attack the government blamed on terrorists, the state-run news agency said. There were no casualties.

• STORY: Arab League observers see 'nothing frightening' in Syria hotspot

The blast happened near the town Rastan in the restive Homs province on Tuesday, SANA reported.

There have been several pipeline attacks since the Syrian uprising began in mid-March, but it is not clear who is behind them at a time when violence across the country is spiraling out control, unearthing long-standing grievances and resentments.

The government blames saboteurs and terrorists for the blasts.

But the opposition accuses the regime of playing on fears of religious extremism and terrorism to rally support behind President Assad, who has portrayed himself as the only force that can stabilize the country.

Syria has banned most foreign journalists from the country and prevented independent reporting, making it difficult to confirm claims from either side.

Rebels: We will 'surprise the regime'
Also on Tuesday, the commander of Syrian armed rebels said he was dissatisfied with the monitors' progress and threatened to wait only a few days before escalating operations with a new style of attack.

"If we feel they (the monitors) are still not serious in a few days, or at most within a week, we will take a decision which will surprise the regime and the whole world," the head of the Free Syrian Army (FSA), Colonel Riad Asaad, told Reuters.

Army defectors and armed rebels, loosely organized under the FSA umbrella, have begun assaults on Syrian state forces in the past months, killing hundreds of soldiers in operations they said are meant to defend the uprising's peaceful protests against President Assad.

Assad told Reuters last week he had ordered a halt to attacks on security forces to give the monitors a chance to operate and "prove that it is the regime that is the criminal."

The colonel, speaking by telephone from his safe haven in southern Turkey, said that the monitors' presence in Syria last week had not stemmed the bloodshed.

A Reuters tally based on activist reports shows that at least 129 people were killed in the team's first week. Other activist groups put the toll as high as 390.

"What is most likely now is that we will start a huge escalation of our operations," Assad said.

He said it would not be an outright declaration of war, but "it will be a transformative shift in terms of the fighting and we hope the Syrian people will stand behind it."

The Arab League said it had secured the release of 3,484 prisoners last week. Before the monitors' arrival, human rights group Avaaz estimated that up to 37,000 were in detention.

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Reuters, The Associated Press and msnbc.com staff contributed to this report.