Syrian officials are blaming what they call a “terrorist group” for blowing up a gas pipeline early Monday, as activists report clashes elsewhere in the country.

Syria's state news agency said the blast occurred near Telkalakh, close to the Lebanese border. There have been several pipeline attacks since a popular uprising began last March against Syrian President Assad al-Bashar, but it is not clear who is responsible for them. Some Syrian cities have faced energy shortages after the attacks.

Meanwhile, the Syrian Observatory for Human Rights said in a statement to the French news agency that clashes killed six members of the country's armed forces and four civilians in Hirak, in the southern province of Daraa.

A day earlier, the British-based activist group reported 72 people killed across the country, including 41 civilians, mostly in the Damascus suburbs and the central cities of Homs and Hama. The reports could not be independently confirmed because Syria bars foreign journalists from operating freely in the country.

Syria's government defended the capital from rebel fighters Sunday, with security forces deployed across the city and around 2,000 troops backed by tanks and armored vehicles launching an assault to retake suburban areas.

Sustained fighting rocked at least four districts around Damascus, the country's largest city and seat of President Assad's power. The offensive pushed into predominantly Sunni Muslim areas of the capital's eastern outskirts that have slipped from government control over the past two weeks.

The Damascus suburbs have seen large demonstrations demanding the removal of Mr. Assad, a member of the minority Alawite sect, an offshoot of Shi'ite Islam that has dominated the mostly Sunni Muslim country for the last five decades.

The Syrian government accuses armed terrorists of driving the revolt against Mr. Assad's 11-year autocratic rule and killing 2,000 security personnel. The United Nations estimated the death toll from the unrest at 5,400 earlier this month before it stopped updating the figure because of difficulties in obtaining information.

Arab League chief Nabil Elaraby said Sunday the regional bloc is in talks with Russia and China to try to persuade them to support an Arab plan for ending the crisis. Elaraby was speaking in Cairo before leaving for New York, where he will formally present the initiative to the U.N. Security Council on Tuesday.

On Monday, the head of the world's largest Muslim body, the Organization of Islamic Cooperation, told the French news agency that he hoped the international community would “take up its responsibilities” in protecting civilians in Syria and ending the bloodshed.

The Arab League plan calls for President Assad to transfer power to a deputy and form a unity government to prepare for national elections under international supervision. The Assad government has rejected the proposals as a violation of Syria's sovereignty.

Russia, Syria's key military ally and a veto-wielding member of the Security Council, opposes efforts by Arab states and Western powers to use the U.N. body to pressure Mr. Assad into stopping his violent crackdown.

Syria's escalating violence prompted the Arab League to suspend the operations of its observer mission in Syria on Saturday. Elaraby said monitors will remain in Damascus until the League's foreign ministers meet next Sunday to decide whether to pull them out of the country.