BEIRUT (AFP) - Lebanon's Western-backed cabinet vowed not to cave in to calls to resign after a massive demonstration led by Hezbollah, as protesters camped outside government offices Saturday.

Friday's massive show of force in central Beirut tightened the political deadlock in the country which has been in near-paralysis because of a fierce power struggle between the pro- and anti-Syrian camps.

Crowds of protesters thronged the streets of the capital on Friday, calling for the ouster of the "corrupt" leadership and temporarily blocking access to Prime Minister Fuad Siniora's government headquarters.

"The massive demonstration... has given Lebanon one of the mostdifficult tests that the country has known in a long while," warned Al-Akhbar daily on Saturday.

The leftist As-Safir daily noted that the protest did not contribute to "open any slight door to resolve the political crisis which remains in deadlock".

The Siniora government, which has received strong public backing from Western and some Arab states, pledged not to bow to the opposition led by Hezbollah. Parliamentary majority leader MP Saad Hariri, the slain premier's son, vowed late Friday that "the Siniora government will not fall because of pressure from the street. However long they continue their protest, it will not fall."

Hezbollah-led demonstrators set up tents and several thousand protesters were still camping early Saturday on at least two main public roads leading to Siniora's offices, after the blockade was eased to allow access from side roads.

The demonstrators vowed to stay until the government gives in, threatening to escalate their actions in the coming days.

Siniora's government has received strong backing from foreign states, including from Jordanian King Abdullah II and Saudi King Abdullah whose ambassador in Beirut held contacts to help ease the blockade.

Siniora on Saturday met visiting British Foreign Secretary Margaret Beckett who expressed her support for his government and called on Lebanon's feuding factions to return to dialogue.

"I reiterated the United Kingdom's support for Lebanon and to the prime minister Siniora," Beckett said in a statement.

"We call on all parties to work together for the good of Lebanon, and to return to dialogue," she said.

U.S. State Department spokesman Tom Casey said Washington denounced what he called "threats of intimidation or violence" which "are aimed at toppling Lebanon's legitimate and democratically elected government".

"And certainly with things like the assassination of Pierre Gemayel and other kinds of events, it's clear that there is a pattern of intimidation, and efforts at intimidation, of those forces aligned with Lebanon's democratically elected government," he added.

Friday's peaceful demonstration came after last week's mass funeral for murdered anti-Syrian industry minister Pierre Gemayel which brought hundreds of thousands of government supporters on to the streets.

Gemayel was the sixth Syria critic to be assassinated in Lebanon over the past two years.

The opposition spearheaded by Hezbollah, which has been bolstered by its fierce resistance during the 34-day summer war with Israel, is demanding a greater share in the government that would also give it power to veto legislation.

But the anti-Syrian camp says the opposition demands are a ploy to avoid the creation of an international tribunal to try suspects in the Hariri murder.

It also wants the departure of Damascus protege President Emile Lahoud, who has been boycotted by Western countries since his mandate was extended in 2004 for three years by a Syrian-inspired constitutional amendment.

Key pro-Syrian officials in Lebanon's power-sharing regime -- the president and parliament speaker Nabih Berri -- do not recognize the rump anti-Damascus cabinet left after the pullout of six pro-Syrian ministers last month.