BEIRUT — The U.N.-Arab League envoy for Syria warned Tuesday that the country could become another Somalia - where al-Qaida-linked militants and warlords battled for decades after the ouster of a dictator - if the civil war is not ended soon.

Battles between regime forces and Syrian rebels left more than 140 people dead across Syria on Tuesday, while the brother of Syria’s parliament speaker was gunned down in Damascus - the latest victim of a wave of assassinations targeting high-ranking supporters of President Bashar Assad’s regime.

The violence aroused new concern about the faltering diplomatic efforts to try to end the conflict, with the U.N. political chief warning that the Syria crisis risks “exploding outward” into Lebanon, Turkey and Israel.

Britain’s prime minister offered the latest long shot - that Assad could be allowed safe passage out of the country if that would guarantee an end to the fighting.

But there has been no sign the Syrian leader is willing to step down. Assad has vowed to militarily crush the nearly 20-month-old rebellion against his rule, and aides say a new president will only be chosen in elections scheduled for 2014.

U.N.-Arab League envoy Lakhdar Brahimi, who, like his predecessor Kofi Annan has been unable to put an end to the conflict, warned the civil war could spiral into new levels of chaos.

“The situation in Syria is very dangerous,” Brahimi said in remarks published Tuesday in the pan-Arab daily Al Hayat. “I believe that if the crisis is not solved ... there will be the danger of Somalization. It will mean the fall of the state, rise of warlords and militias.”

Somalia has been mired in conflict for more than two decades after warlords overthrew the east African nation’s longtime dictator in 1991 and then turned on each other. The government, backed by African Union troops, is currently battling Islamist extremist rebels linked to al-Qaida.

Syria, by comparison, has always had a strong central government, and despite losinglarge swathes of territory, the regime still maintains a grip on many parts of the country, including Damascus, the seat of Assad’s power, where basic government services still function.

But if the regime collapses, the country could fast shatter along multiple fault lines, leading to protracted bloodshed.

The predominantly Sunni nation is a patchwork of religious and ethnic groups. The regime is led by Assad’s Alawite minority, an offshoot of Shiite Islam, but there are also considerable Kurdish and Christian populations.

The conflict’s already increasing sectarian overtones suggest any power vacuum could usher in renewed violence. Predominantly Kurdish areas in the north and Alawite majority areas in the central coastal mountains could spin away, and mixed areas - already hard hit by the conflict - could plunge further into conflict.

At the United Nations, Jeffrey Feltman, the U.N. undersecretary-general for political affairs, warned that the escalating violence will lead Syria “to its destruction” and threatens neighboring Lebanon, Turkey and Israel.

“The situation inside Syria is turning grimmer every day, and the risk is growing that this crisis could explode outward into an already volatile region,” he told a meeting ofthe Security Council.

More than 36,000 people have perished in the fighting, according to activists, and the death toll rises daily.

On Tuesday, more than 140 people were killed in violence across the country, activists said, including a series of airstrikes on rebel strongholds in the suburbs of Damascus. Among the dead were at least 13 people who died when three bombs exploded in the al-Wuroud district on the capital’s northwestern edge, near housing for the elite Republican Guard, which is led by Assad’s brother Maher Assad.

A former Syrian air force general who was also the country’s first astronaut said Tuesday that only about onethird of Syria’s fighter pilots are carrying out the daily bombing raids of rebel strongholds because President Bashar Assad’s regime cannot count on the loyalty of the rest.

Maj. Gen. Mohammed Fares, who defected in August and joined the main umbrella group for regime opponents, the Syrian National Council, also said the regime’s combat aircraft are aging and running short of spare parts, but that Assad still has hundreds of planes at his disposal.

The brother of Syria’s parliament speaker was killed in a hail of bullets by gunmen who targeted him as he drove to work in Damascus. Mohammed Osama Laham, the brother of Speaker Jihad Laham, was the latest government supporter to be targetedfor assassination.

Diplomacy has been deadlocked at the U.N., where Syria’s allies Russia and China have repeatedly blocked attempts to approve harsher sanctions in the Security Council.

British Prime Minister David Cameron suggested Tuesday that Assad could be allowed safe passage out of the country if that would guarantee an end to the nation’s civil war.

Asked in an interview with Al Arabiya television if he would contemplate offering Assad an exit route, Cameron said the international community would consider anything “to get that man out of the country and to have a safe transition in Syria.”

In London, officials said Cameron was not suggesting Assad could escape potential international prosecution if he were to be granted passage out of Syria. They also said therewere no talks aimed at crafting an exit deal.

The Turkish state news agency Anadolu reported that seven generals, meanwhile, fled into neighboring Turkey, the latest of dozens of top-rankingmilitary officers to abandon the regime. More than 110,000 Syrians have sought refuge in Turkey since the uprising began in March 2011.

In Jordan, which also borders Syria, visiting Russian Foreign Minister Sergey Lavrov met with Riad Hijab, the former Syrian prime minister who defected to Jordan in August. It was a rare high-level contact between Moscow and a Syrian opposition figure.

Lavrov said the talks were meant to get firsthand information from the Syrian opposition on how they view a solution to the civil war.

Meanwhile, in the Gaza Strip, a spokesman for the Palestinian group Hamas, Ayman Taha, said the Syrian government had sealed Hamas’ offices in Damascus, finalizing the break between the Islamic militant group and its former patron after Hamas switched sides to support the armed rebellion against Assad’s regime.

Information for this article was contributed by Dale Gavlak, Suzan Fraser, David Stringer, Abdullah al-Shihri and Karin Laub of The Associated Press.

Front Section, Pages 8 on 11/07/2012