The three principal Moslem and Christian militias in Lebanon agreed Thursday to withdraw from Beirut and its suburbs in line with the government's plan to end the 15-year-old civil war.

President Elias Hrawi's government obtained agreement from Samir Geagea's right-wing Christian Lebanese Forces militia, Nabih Berri's moderate Shiite Amal militia and Druse warlord Walid Jumblatt's Progressive Socialist Party.The pullout area covers what is known as "greater Beirut" - the Moslem and Christian sectors of a capital divided since the outbreak of the civil war in 1975, as well as its immediate suburbs.

A government source, speaking on condition of anonymity, said the "zero hour for launching the greater Beirut plan would most probably be set before early next week."

Hrawi's Syrian-backed government announced after a three-hour meeting Wednesday its decision to "spread state authority" over the area but set no deadline for carrying out the plan to create a militia-free capital.

The pro-Iranian Hezbollah - the fundamentalist Shiite Moslem umbrella organization for groups holding U.S. and other foreign hostages - Thursday said only that it will announce its decision after holding talks.

It did not elaborate.

On Wednesday, police said Hezbollah, or Party of God, handed over some Beirut positions to government troops but maintained its stronghold in the south Beirut slums of Bir Abed, Hay Madi and Moawad.

Agriculture Minister Mohsen Dalloul and Defense Minister Albert Mansour, assigned by the government to follow up the greater Beirut plan with militia leaders, were to "put the final touches to the mechanism of the militias' withdrawal," the government said.

He said the army command of Gen. Emile Lahoud has prepared two brigades to fill in the vacuum resulting from the militias' withdrawal.

The greater Beirut plan was announced 11 days after Lebanese and Syrian forces crushed rebel Gen. Michel Aoun's 11-month mutiny in an eight-hour assault.