BEIRUT — Lebanon's Syrian-backed factions finally agreed on a unity government proposed by their pro-Western rivals on Saturday, ending a four-month deadlock in the deeply divided country.

The announcement by the opposition coalition dominated by the militant Hezbollah group came after a meeting late Friday night between the groups' leaders including Hassan Nasrallah. Prime Minister-designate Saad Hariri was informed the next day.

The agreement would end a political deadlock that has threatened to send the fragile nation spiraling back into violence.

Hariri has been trying to form a Cabinet since June, when his western-backed coalition narrowly defeated Hezbollah and their allies and retained a slim majority in the 128-member legislature.

Both groups agreed from the beginning on a complicated power sharing formula that gives Hariri's coalition 15 seats in the next government and the Hezbollah-led minority 10 seats, with five other seats to be filled by President Michel Suleiman, who is seen as a neutral figure.

Since then they had not been able to agree on what posts each group will take.

The latest developments also come after Syria and Saudi Arabia, seen as patrons of the rival factions, improved relations that have been tense since 2005.

Hariri's Cabinet lineup appears to have given the opposition the seats they have been demanding for months, including the Telecommunications Ministry.

A Hezbollah statement issued Saturday said the opposition leaders agreed during the meeting "to go ahead with the formation of a national unity government according to what was agreed upon during negotiations."

It added that they "hope that this step will be for the good of Lebanon and its people."

During the months-long negotiations, one of the most contentious points was the demand by Hezbollah and its allies that Jibran Bassil stay on as telecommunications minister, a sensitive post for security reasons.

Hariri refused to give the position to the opposition.

Hariri ultimately relented, but only if the minister was not Bassil, but rather another member of his party. Bassil will become Minister of Power and Hydraulic Resources in the future Cabinet, according to the daily Al-Akhbar that is close to Hezbollah.

The paper said Hezbollah, which currently has one minister, will have two Cabinet members in the next government.