BEIRUT -- The Syrian-backed government of Lebanon stepped down yesterday, collapsing under a groundswell of street protests, candlelight vigils, and international pressure to end Damascus's domination of its neighbor.
As 25,000 demonstrators thronged in the streets outside, Prime Minister Omar Karami, an ally of Syria, stood before Parliament and announced that he would quit his job and dismantle his Cabinet.
The decision was apparently spontaneous. Pro-Syrian lawmakers appeared stunned and members of the opposition rose to their feet in a standing ovation.
The resignation was a triumph for a swelling Lebanese opposition, which has been calling for Syria to withdraw its soldiers and disentangle its intelligence services from Lebanon's institutions. Tensions had been mounting since the Feb. 14 assassination of former Lebanese Prime Minister Rafik Hariri, which many blamed on Syria.
The fall of the government marked a rare flexing of public will in the Arab world, where similar protests have been brutally suppressed.
Minutes after Karami announced he was stepping down, jubilant demonstrators -- shouting, waving flags, and handing red roses to soldiers -- demanded that Syrian-backed President Emile Lahoud bow out, too, and pressed on with their calls for Syria to withdraw its troops from the country.
Syria was silent about the changes in Beirut, where it ruled unopposed for years, even deciding on Lebanon's leaders, after deploying troops ostensibly as peacekeepers during the 1975-90 civil war.
But the dramatic developments, which were reminiscent of Ukraine's peaceful ''orange revolution" and broadcast live across the Arab world -- could provoke a strong response from Syria, which deploys 15,000 troops in Lebanon. It also could plunge this nation of 3.5 million back into a period of uncertainty, political vacuum, or worse.
In Washington, US officials called the government's dismantling a victory for the Lebanese people and their efforts to hold new elections. White House spokesman Scott McClellan stressed the selection of a new government ''should be free of all foreign interference. That means Syrian military forces and intelligence personnel need to leave the country," he said. ''That will help ensure that elections are free and fair."
The Lebanon Parliament had gathered to debate a no-confidence motion, but the government was expected to survive. After hours of bickering, Karami announced his decision to dissolve the government.
''Out of concern that the government does not become an obstacle to the good of the country, I announce the resignation of the government I had the honor to lead," Karami told lawmakers.
A visibly rattled parliament Speaker Nabih Berri told Karami: ''I think I deserved to have been told beforehand." A few blocks away, protesters greeted the surprise resignation with rapturous applause. Thousands of Lebanese had gathered in Martyrs' Square, flouting an official ban on demonstrations and evading the intense security clampdown that had closed off the main thoroughfares into the capital.
''We didn't have a chance to speak before," said Marta Bou Raad, a 70-year-old mother of five who joined the protest. ''We were afraid that we would be hurt or arrested, but we're not afraid anymore."
Opposition lawmakers, their shoulders draped in the red-and-white scarves that have come to symbolize their movement, emerged from parliament to a hero's welcome in the square.
''The people of a united Lebanon brought down the government," Mohammed Qabbani, a lawmaker from Hariri's parliamentary bloc told the crowd. ''Now we want the truth, we want to know who killed Rafik Hariri."
''Syria, Syria!" shouted the crowd.
After the Cabinet resigned, Interior Minister Suleiman Franjieh said he was comfortable with the evening's turn of events.
''It was a burden on our shoulders, and now it has been released. Let others carry the burden," the pro-Damascus minister said. ''The main thing is that we did this without spilling blood."
In addition to its soldiers in Lebanon, Syria uses thousands of intelligence agents to maintain control on Lebanese politics.
Syrian officials and their Lebanese proxies appeared to be waiting in recent days for street protests to quell. Public outrage was stoked in part by Lebanon's refusal to permit an international investigation into Hariri's death, and encouraged by angry calls from the United States, France, and the United Nations for Syrian troops to leave Lebanon.
In one sign Syria has no intention of just packing up and leaving, Syrian President Bashar Assad said in remarks published yesterday that there will be a price for Syrian troop withdrawal: a settlement with Israel.
''Under a technical point of view, the withdrawal can happen by the end of the year," Assad told the Italian newspaper La Repubblica. ''But under a strategic point of view, it will only happen if we obtain serious guarantees. In one word: peace."
Syrian officials announced last week that they would withdraw their soldiers to Lebanon's Bekaa Valley, closer to the Syrian border. But a full withdrawal is out of the question without a peace deal, Assad said.
The UN Security Council last year passed a resolution demanding a Syrian withdrawal, a move described by both Syrian and pro-Syria Lebanese officials as tampering with the ''brotherly relations" between the two countries.
''The government should have resigned a long time ago," said Farid Khazen, chair of political studies at the American University of Beirut. ''It lacks credibility and popularity, and it's run by Syria."
The fall of the government clears the path for Lebanon to set up an interim government to prepare parliamentary elections, scheduled to be held this spring. The voting has been widely anticipated as a popular referendum on Syria's influence on Lebanon.
President Lahoud quickly accepted the resignation of Karami's 4-month-old Cabinet, which replaced Hariri's government, and asked Karami to stay on in a caretaker capacity until a new government is formed.
Opposition leaders -- a diverse group of Muslim, Druse and Christians -- demanded a neutral government to organize parliamentary elections this spring and to investigate Hariri's murder.
Material from the Associated Press was included in this report.