The Arab League halted its observer mission to Syria on Saturday, sharply criticizing the regime of President Bashar Assad for escalating violence in recent days that has killed at least 80 people across the country.

The rising bloodshed has added urgency to new attempts by Arab and Western countries to find a resolution to the 10 months of violence that according to the United Nations has killed at least 5,400 people as Assad seeks to crush persistent protests demanding an end to his rule.

But the initiatives continue to face two major obstacles: Damascus' rejection of an Arab peace plan which it says impinges on its sovereignty, and Russia's willingness to use its U.N. Security Council veto to protect Syria from sanctions.

Syrian government forces clashed with anti-regime army defectors across the country on Saturday. At least nine were reported killed in the clashes and other violence. The new deaths come after two days of bloody turmoil killed at least 74 people, including small children.

The month-old Arab observer mission in Syria had come under widespread criticism for failing to bring a halt to the regime's crackdown. Gulf states led by Saudi Arabia pulled out of the mission Tuesday, asking the U.N. Security Council to intervene.

League Secretary-General Nabil Elaraby said in a statement that after discussions with Arab foreign ministers, the organization decided to halt the observers' work immediately because of the increasing violence, until the League's council can meet to decide the mission's fate.

He blamed Damascus for the spike in bloodshed, saying the regime has "resorted to escalating the military option in complete violation of (its) commitments" to end the crackdown, Elaraby said. He said the victims of the violence have been "innocent citizens," in an implicit rejection of Syria's claims that it is fighting "terrorists."

Elaraby's deputy, Ahmed Ben Heli, told reporters that the around 100 observers will remain in Damascus while their mission is "reevaluated."

Ben Heli suggested the observers could resume their work later. Asked if the mission would be withdrawn, he said the halt was "forced by events" and aimed to ensure the observers' safety, but he spoke of a possible "new map" of places where the teams would visit, and said the mission would wait to see what new personnel and logistical help the League would give it.

Elaraby and the prime minister of Qatar were set to leave for New York on Sunday to seek U.N. support for the latest Arab plan to end Syria's crisis. The plans calls for a two-month transition to a unity government, with Assad giving his vice president full powers to work with the proposed government.

Syria has rejected the proposal, saying it violates its sovereignty. Elaraby had previously been due to travel Saturday, but his trip was pushed back to Sunday with no explanation.

The U.N. Security Council began closed-door negotiations Friday on a new Arab-European draft resolution aimed at resolving the crisis, but Russia's envoy said he could not back the current language as it stands.

Any resolution faces strong opposition from China and Russia, and both nations have veto power. Russia's U.N. Ambassador Vitaly Churkin told reporters that the text introduced by new Arab Security Council member Morocco has "red lines" for Moscow, but he's willing to "engage" with the resolution's sponsors.

Churkin said those lines include any indication of sanctions, including an arms embargo. "We need to concentrate on establishing political dialogue," he said.

Arab League chief Elaraby has been holding talks with Russia's foreign minister over the crisis ahead of the visit to the U.N., Ben Heli said.

In the bloodiest incident reported on Saturday, Syria's state-run news agency SANA said "terrorists" ambushed a bus carrying army officers near the tense Damascus suburb of Douma, killing seven of them.

Although Damascus has been relatively quiet since the uprising began, its suburbs have witnessed intense anti-regime protests and army defectors have become more visible and active in the past few months.

Syrian opposition groups had no immediate reports on the ambush in Douma, but the Local Coordination Councils activist network said government troops were attacking several other Damascus suburbs _ Kfar Batna, Saqba, Jisreen and Arbeen _ using tanks and armored personnel carriers. It added that defectors were fighting advancing troops.

In the eastern oil-rich province of Deir el-Zour, an oil pipeline took a direct hit and caught fire as government troops shelled a town, activists said.

The British-based Syrian Observatory for Human Rights and the LCC said the early morning shelling of the town of Qoriah killed at least one person and set the pipeline on fire.

Syria's state-run media blamed anti-government "terrorists" for the attack, saying the fire was extinguished four hours later. It said the pipeline carried crude oil from al-Omar field to a station in the area.

SANA also reported that Syrian troops prevented gunmen from crossing from neighboring Turkey into the northwestern province of Idlib. SANA said a Syrian soldier was wounded while many of the infiltrators were either killed or wounded, adding that the rest returned to Turkey.

The Free Syrian Army force of anti-regime military defectors is based in Turkey, and its fighters frequently try to cross into Syria through the mountainous border area in the northwest.

The LCC and the Observatory also reported intense fighting between troops and defectors in the town of Rastan near the restive central city of Homs.

The observatory said at least two people were killed across the country in Saturday's violence while the LCC said six died, most of them in the central city of Homs, which has been one of the areas hardest hit by government crackdowns.

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Associated Press writers Aya Batrawy in Cairo, and Albert Aji in Damascus, Syria, contributed to this report.

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Bassem Mroue can be reached on twitter at http://twitter.com/bmroue