BEIRUT, Lebanon - Lebanon's political rift has deepened on the third day of a protest led by the Shiite militant group Hezbollah and Christian opposition supporters, with the Western-backed government vowing to resist calls to resign.

The open-ended rally aims to bring down Prime Minister Fuad Siniora's government, which was deserted by six pro-Syrian ministers last month amid accusations of corruption and impotence after the July-August war with Israel.

Siniora and other leading lawmakers in the anti-Syrian parliament majority have pledged to stay in their elected posts as the deadlock tightens in Lebanon's power struggle between pro- and anti-Syrian camps.

"Protest is no solution. I am going to stay as long as I am prime minister by the will of the majority," Siniora told reporters on Sunday.

Around 100,000 people took part in the rally on Sunday, an AFP correspondent said, after several hundred opposition protesters from various Shiite and Christian factions camped on the doorstep of the government for a second straight night.

Hundreds of thousands of opposition protesters took part in Friday's initial march for a unity government.

On Saturday, several thousand demonstrators blocked at least two main roads leading to Siniora's offices, after the overall blockade was eased to allow access from side streets.

The main rally, which has seen no incidents of violence, continued into the night, as mostly Shiite demonstrators waved Lebanese flags to the tune of Hezbollah war hymns and cheered speeches by prominent figures who blasted Siniora.

But four people were injured in a street fight after protesters drove through a Sunni neighborhood where most inhabitants are loyal to the anti-Syrian dominated parliament and blows were exchanged. No gunfire was reported.

Speaking from inside government headquarters, Druze chief and anti-Syrian MP Walid Jumblatt reiterated the government's call for a return to talks over Lebanon's tense political deadlock.

"We will be patient. When they are convinced there is no other way, when they make up their mind that only dialogue can lead to a breakthrough, then we will be ready for talks," he said.

The Siniora government has received strong public backing from Western and some Arab states, including Saudi Arabia and Egypt, while Syria threw its support behind the opposition "and its national forces who confronted the Israeli aggression with heroism", referring to July-August war with Hezbollah.

Arab League secretary general Amr Mussa described Lebanon's political crisis as "serious" on his arrival in Beirut for talks with the deadlocked parties.

"We are aware of the dangers and we hope that it won't escalate," he said after meeting Siniora.

Egyptian President Hosni Mubarak on Saturday criticized the demonstrations as "very unwise, for I fear these protests are sectarian and that reinforcements will come from outside to broaden the demonstrations, which would lead to fighting and destruction".

Israel said Sunday it was following the events in Lebanon "with the utmost attention", while Washington has denounced "threats... aimed at toppling Lebanon's legitimate and democratically elected government".

Siniora's government has appealed for fresh talks with the opposition over a deadlock which threatens to block the government's legislative program, including its centerpiece plans for an international tribunal to try suspects in the 2005 murder of former premier Rafiq Hariri, which was widely blamed on Syria.

Only parliament speaker Nabih Berri, a pro-Syrian Shiite leader whose supporters joined the opposition protest, has the authority to present draft legislation to parliament.

"I appeal to Mr Berri to call for a resumption of dialogue," Siniora said on Saturday.

Friday's demonstration came after the previous week's mass funeral for murdered anti-Syrian industry minister Pierre Gemayel brought hundreds of thousands of government supporters onto the same streets of downtown Beirut.

The opposition is demanding a greater say in the government, which it charges has been riding roughshod over the power-sharing arrangements in force since Lebanon's devastating 1975-1990 civil war.

But the anti-Damascus camp says the opposition demands are a ploy at the behest of their Syrian sponsors to avoid the formation of the proposed international tribunal to try suspects in Hariri's murder. -AFP