BEIRUT, Lebanon - Thousands of supporters of the Iranian-backed Hezbollah, which is seeking to bring down the pro-Western government, clashed with government supporters and blocked highways leading into the Lebanese capital yesterday, raising fears that the political crisis might lead to open sectarian conflict.

At least three people died and 100 more were injured throughout the country in the violence, the worst since Hezbollah began demanding more political power late last year, police officials said. Mobs of men burned tires, set cars on fire, and fought occasional gun battles with their political opponents.

In some cases, opponents yelled slogans with clear sectarian undertones, an especially frightening development for those who lived through the country's bloody civil war from 1975 to 1990.

By nightfall, the opposition began removing most of the makeshift roadblocks in Beirut and announced that the protest was over. But the group warned that more protests could follow.

"This is a one-day show of force for the time being," said Paul Salem, director of the Carnegie Middle East Center in Beirut.

The opposition has accused Prime Minister Fuad Saniora of corruption and graft and has dismissed him as a Western puppet. They have called for his resignation and for a "unity" government that would ultimately give Hezbollah and its allies veto power.

Yesterday's violence came just two days before a crucial conference of donor nations in Paris to secure $5 billion in loans and aid to rebuild parts of Lebanon destroyed in the war between Israel and Hezbollah last summer. Hezbollah has vied with the government to provide help to residents in the country's south and in Beirut's southern suburbs, which were the worst hit during the monthlong war.

Saniora insisted yesterday that nothing would stop him from traveling to Paris.

"I urge you to think clearly where they want to take you, away from your interest and that of the country," Saniora said, addressing the protesters on television. "We will stay together against intimidation. We will stand together against strife."

The turmoil started at dawn, when groups of protesters set up roadblocks along major thoroughfares leading into Beirut, using burning tires, trucks and rubble . They set fire to vehicles and, on several instances, were filmed attacking cars trying to pass their cordon.

In Beirut, many of the clashes were in mixed neighborhoods, where young men on either side of the widening political divide shouted epithets and hurled stones at each other.

Along one major thoroughfare, the men got into a brawl amid sporadic gunfire. One side raised photos of Sheikh Nasrallah, a Shiite, and burned photographs of former Lebanese Prime Minister Rafik al-Hariri, a Sunni whose assassination in 2005 set off Lebanon's latest political turmoil. The other side lined up across the street and raised photographs of three Sunnis: Hariri, Saniora and Saddam Hussein.

On the coastal highway north of Beirut, supporters of Gen. Michel Aoun, leader of the Free Patriotic Movement, a Christian group and a Hezbollah ally, clashed with men loyal to Samir Geagea, a government ally, in especially violent clashes.

"It is a revolution against us, they are attacking us with stones and burning pictures of our leaders and blocking our roads," said Ibrahim Hijazi, 29, who said he supported the government.

Opposition leaders insisted their supporters were protesting "peacefully" when residents began hurling stones at them. They also said they would not allow themselves to be dragged into sectarian conflict.

Saniora, speaking on Lebanese television last night, remained defiant, insisting he would not step down and that he still enjoyed the support of the country.

"We are at a crossroads today," Saniora said. "Let's choose coexistence, civic peace, unity and stability, freedom and democracy instead of roads that will further split us and waste our energy and increase chances for violence and terrorism."

According to the Associated Press, two of the deaths were in Tripoli, a northern city, where two groups - one largely Sunni and one Alawite, a Shiite Muslim offshoot - fought each other in a gun battle. The other death occurred during a gunfight in the Christian Batroun region, the AP said.

Masked Gunmen Storm Gaza Resort

Masked gunmen claiming

to be from al-Qaeda stormed a Gaza beach resort yesterday and blew up a reception hall in an attack aimed at intimidating an ally of Palestinian Authority President Mahmoud Abbas, a witness said.

No one was hurt, because the resort was empty, except for a few guards. But the assault threatened to spark a new wave of internal violence, casting a cloud over the

next round of talks on forming a unity government between Abbas' Fatah and the rival Hamas.

About 40 gunmen swarmed into the resort, which

was a favorite of Israelis before Palestinian-Israeli violence erupted in 2000.

Resort manager Yousef Sari said the gunmen had a warning for Fatah's Mohammed Dahlan, an Abbas confidant. Dahlan

has been rumored to own the resort, but he says he does not.

"Tell Dahlan al-Qaeda has arrived in Gaza and his property and assets are targets," Sari quoted the attackers as saying.

Dahlan, one of the most feared and powerful figures in Gaza, served in senior security posts when Fatah was in power and cracked down on Hamas. He maintains control over armed forces in Gaza even though Fatah was ousted by Hamas in elections a year ago.

- Associated Press