Prime Minister Fuad Saniora, emboldened by Arab and international support for his U.S.-backed government, vowed on Sunday to stay in office despite Hezbollah protests that aim to pressure him into resigning.

While two rival religious Masses were in progress, thousands of flag-waving Hezbollah supporters and their allies from pro-Syrian parties continued their open-ended sit-in calling on Saniora to step down and pave the way for the formation of a new government.

Amid the sound of revolutionary and nationalist songs blaring from protesters' tents set up in the heart of Beirut, Lebanon's capital, a Mass was held at Saniora's office in memory of Industry Minister Pierre Gemayel who was assassinated by gunmen in a Beirut suburb last month.

The service, attended by the premier, some of his anti-Syria bloc in the Cabinet and parliament, and Gemayel's family members, including his father, a former president, appeared to be a show of solidarity with the government, which Hezbollah and its allies have vowed to topple.

A few meters away, a rival Mass organized by supporters of Christian leader Michel Aoun, an ally of the Shiite Muslim Hezbollah, was held at the St. George Cathedral for Lebanon's salvation.

From his office, Saniora vowed Sunday to continue as premier and asserted that the protests would not achieve their goal. He hinted that the anti-Syrian coalition backing him might stage counter protests if the opposition's sit-in drags on.

"A solution to any problem does not come through the street because this means might trigger a counter-means and therefore, we will not reach any result," Saniora told reporters after the Mass.

He stressed that the "best way" to resolve the deepening political crisis was by returning to "constitutional institutions" and urged Parliament Speaker Nabih Berri, a Hezbollah ally, to try to revive dialogue among the rival factions.

Saniora warned that any attempts by Hezbollah's supporters to storm his office, ringed by hundreds of police and soldiers, tanks and armored vehicles, would lead to "a major and serious problem." The prime minister, a Sunni, appeared to be cautioning against the possibility of open fighting between Sunnis and Shiites.

Thousands of Hezbollah supporters began an open-ended sit in Friday in central Beirut.

The political crisis, which has disrupted life in the capital's commercial district and raised fears of violence between the country's pro- and anti-Syria forces, showed no sign of easing as each side refuses to modify its position.

"This government will continue as long as it enjoys the support and backing of the constitutional institutions in the country, most importantly parliament," said Saniora, who received support from Arab and European leaders Saturday.

Druse leader Walid Jumblatt, a leading figure in the anti-Syrian coalition, attended Sunday's Mass to show support for the government.

"We are here in Lebanon's government house with Fuad Saniora, the legitimate and constitutional prime minister of all of Lebanon," Jumblatt told reporters after the Mass in memory of Gemayel.

Asked how the anti-Syrian coalition will respond if the opposition's protests dragged on indefinitely, he said, "We will show patience, peacefully and democratically. When they [the opposition] become convinced that there is no way but dialogue, we are ready for it."

Arab League Secretary-General Amr Moussa was due in Beirut later Sunday for talks with Saniora and Berri on ways of defusing the escalating tensions.

Shouts of, "Saniora out!" rang out among the protesters after the premier and Druse leader spoke.

Hezbollah's support among Shiite Muslims grew after the strong showing of its guerrillas during the summer war with Israel.

Six pro-Hezbollah ministers resigned from the Cabinet last month after Saniora and his slim anti-Syrian majority in parliament rejected the group's demand for a new national unity government that would effectively give it and its allies veto power.

The current government is largely backed by Sunni Muslims and Christians who oppose involvement in the country's affairs by neighboring Syria, which was forced to end a nearly three-decade military occupation last year.

Saniora and his supporters call Hezbollah's campaign a coup attempt led by Syria and its ally Iran, a stance echoed by Washington, which is seeking to counter Iranian influence in a number areas of the Middle East.

Support for Saniora also came from France, Britain, Italy, Germany, Egypt and from Palestinian Authority leader, Mahmoud Abbas.

Hezbollah, an ally of Syria that is backed by many Shiite Muslims and some Christians, contends the fight is against American influence, saying the United States now dominates Lebanon in the interests of Israel.