BEIRUT - A high-level Arab League delegation starts a mediation mission in Beirut on Wednesday to try to pull Lebanon back from the brink of a new civil war.

The delegation will seek to defuse tension between the U.S.-backed governing coalition and Iranian-backed Hezbollah, which routed its rivals in the worst spate of violence among Lebanese since the 1975-90 civil war. At least 81 people have been killed.

"The Arab League mission opens a window for a solution," a senior Lebanese political source said. "It has specific steps that raise hopes of a compromise deal."

Arab foreign ministers had agreed to send the mission, to be led by Qatari Prime Minister Sheikh Hamad bin Jassim bin Jabr al-Thani and Arab League chief Amr Moussa, after Hezbollah briefly seized control of the Muslim part of Beirut before handing it over to the army last week.

If it succeeds in easing tension, the Arab delegation is expected to invite the rival leaders to Qatar for talks aimed at resolving their protracted political conflict, the source said.

The broader political dispute revolves around how to share power in cabinet and a new parliamentary election law. The 18-month-long conflict - a standoff between an anti-Syrian cabinet and opposition forces backed by Damascus - has left Lebanon without a president since November.

Nabih Berri, who is speaker of parliament and also a prominent opposition leader, said the government must annul two decisions it took against Hezbollah last week and which triggered the group's partial takeover of Beirut.

"That is the way to the solution and the path to dialogue," Berri, leader of the Shi'ite Amal movement, told the pro-opposition al-Akhbar newspaper. "The alternative to dialogue leaves difficult options. This is what we don't want."

Prime Minister Fouad Siniora has called the cabinet for a meeting later on Wednesday. The government could annul the decisions at the session.

FEARS OF STRIFE

The decision to ban Hezbollah's communications network was seen as a declaration of war by the group, which routed its rivals in six days of fighting that erupted on May 7. Hezbollah was also infuriated by the cabinet's move to fire Beirut airport's security chief, who is close to the group.

The fighting quickly took sectarian tones, raising concerns Lebanon was edging towards wider civil strife among Druze and Sunni supporters of the governing coalition and Shi'ites who back Hezbollah.

Hezbollah activists began to remove roadblocks on the airport road on Wednesday to give the Arab mediators passage to the city.

Governing coalition leader Saad al-Hariri, Lebanon's most powerful Sunni politician, pledged on Tuesday there would be no political surrender to what he called an attempt by Hezbollah and its Syrian and Iranian backers to impose their will.

He welcomed Arab mediation and left the door open for compromise. "I hope that with the Arab delegation we will find a solution," Hariri said. "We have reached the point of sectarian strife and everyone must compromise."

U.S. President George W. Bush is to consult allies on how to assist Lebanon when he visits the region this week.

Saudi Arabia, also a backer of the governing coalition, has said Hezbollah's actions, if backed by Iran, could threaten Tehran's ties with Arab states. Iran has blamed the United States for the violence in Lebanon.