The Hizbullah-led opposition in Lebanon announced on Tuesday evening it would call off the roadblocks and the nationwide general strike that sparked heavy unrest, saying it had delivered a warning to the government. But it threatened more protests. Hizbullah-led protesters burned tires and cars and clashed with government supporters, paralyzing Beirut and areas across Lebanon in the worst violence yet in the pro-Iranian group's campaign to topple US-backed Prime Minister Fuad Saniora. At least three people were killed and dozens injured Tuesday as the two camps battled each other around street barricades with stone-throwing and in some cases gunfire. Black smoke poured into the sky over Beirut from burning roadblocks. The fighting quickly took on a dangerous sectarian tone in a country whose divided communities fought a bloody 1975-1990 civil war. Gunmen from neighboring districts in the northern city of Tripoli - one largely Sunni Muslim, the other largely Alawites, a Shiite Muslim offshoot - fought each other, causing two of the fatalities. The day gave a frightening glimpse of how quickly the confrontation between Saniora's government and the Iranian-backed Hizbullah and its allies could spiral out of control, enflame tensions among Sunnis, Shi'ites and Christians and throw Lebanon into deeper turmoil. Opposition supporters began withdrawing from their street blockades, leaving behind burning tires, concrete blocks and debris. At one abandoned roadblock in the north of Beirut, a fire engine extinguished the burning tires. Suleiman Franjieh, a Christian opposition leader, told Hezbollah's Al-Manar TV the next steps "will be nothing compared to what we saw today" if the government does not respond to the opposition's demands. The Hizbullah-led opposition is growing increasingly frustrated after two months of sit-in protests outside Saniora's offices in downtown Beirut failed to force him to step down or form a new government giving the opposition more power. Saniora vowed not to give in, saying in a televised address: "We will stand together against intimidation and to confront sedition." But he repeated his willingness to discuss a political solution to the impasse and called for a special session of Parliament. The violence called into question whether Saniora will be able to attend a conference of donor nations in Paris on Thursday aimed at raising billions in aid for rebuilding the devastation wreaked on Lebanon by last summer's Israel-Hizbullah war. Saniora has been expected to attend and the suspension of the strike increased the likelihood. But the government has not made a formal announcement about his travel plans. Cabinet Minister Ahmed Fatfat told Lebanon's New TV that the economy and finance ministers already were in Paris. The money could boost the Saniora government. But months of political crisis have slowed the reconstruction effort, paralyzing the government - and if the chaos grows it could mean any new money won't be properly used. In Dubai, US Undersecretary of State Nicholas Burns said the international community must support the Saniora government against "those who would destabilize it." The day's turmoil brought Beirut airport to a halt, with Hezbollah supporters building earthen barricades on roads to the facility. Their cars blocked, departing passengers wheeled suitcases past protesters and burning tires on the highway leading to the airport. Airlines canceled flights later in the day, and 400 passengers were stranded at the terminal. Among those stuck for hours were 146 Chinese troops who were joining UN peacekeepers in south Lebanon. Tuesday's violence grew out of a nationwide general strike called by Hizbullah and its allies to push for a new government in which they would have veto power over major decisions. The opposition accuses Saniora's government of not representing them and of allying the country too closely to the United States. Protesters set up barricades of burning tires and cars at major intersections in Beirut and other cities. In many areas, violence erupted when government backers moved in to confront the protesters. "We've been protesting (peacefully) for 52 days and our calls went unanswered," said Tony Younes, who was blocking a road in northern Beirut with other followers of Michel Aoun, Hizbullah's top Christian ally. "Today, we escalated. Tomorrow we will escalate more. And we will continue until the fall of the government," he said. Security forces struggled to contain the violence. In some places, officers moved between battling camps of protesters amid a rain of stones. In others, they broke down barricades only to see them rebuilt. In the Christian Batroun region, government supporters and opponents fired on each other, killing a pro-Saniora protester. Across the country, 44 people sustained gunshot wounds and about 80 others were injured in fistfights or stone-throwing attacks. Lebanon's Sunnis largely support Saniora, while the Shi'ites back Hezbollah. Many Christians support Saniora, but the pro-Hizbullah Aoun also has a large following. Across the country, many businesses closed as workers stayed home, either in support of the strike or because of blocked roads. Some schools closed because of the unrest; others opened and quickly sent pupils home. "My mother is sick in the hospital and I want to go see her," cried Jean Kahwaji, who was trying to maneuver his car around burning tires east of Beirut.