The assassination of Brig. Gen. Wissam al-Hassan in a massive car bomb Friday threatens to shatter the fragile political balance in Lebanon, a country plagued by decades of strife - much of it linked to political and military domination by Damascus.
"The Sunni blood is boiling!" the crowd chanted as hundreds of people clashed with security forces. More than 100 protesters broke through a police cordon of concertina wire and metal gates, putting them within 50 yards (meters) of the entrance to the palace.
Authorities responded with tear gas and several officers fired machine guns and rifles in the air. One plain clothes guard pulled a pistol from his belt and fired over protesters' heads. Then a roar of automatic gunfire erupted, sending the protesters scattering for cover.
It was unclear if the guards fired live bullets or blanks, but no protesters were reported injured by gunfire. Several were overcome by tear gas, and the government's media office said 15 guards were injured.
The killing of al-Hassan has laid bare some of Lebanon's most intractable issues: the country's dark history of sectarian divisions, its links to the powerful regime in Damascus and the role of Hezbollah, the Shiite militant group that dominates Lebanon's government and is Syria's closest ally.
Many fear the crisis could lead to the kind of street protests and violence that have been the scourge of this Arab country of 4 million people for years, including a devastating 1975-1990 civil war and sectarian battles between Sunnis and Shiites in 2008.
Al-Hassan, 47, was a powerful opponent of Syria in Lebanon. He headed an investigation over the summer that led to the arrest of former Information Minister Michel Samaha, one of Syria's most loyal allies in Lebanon.
He also led the inquiry that implicated Syria and Hezbollah in the assassination of former Prime Minister Rafik Hariri in 2005.
Al-Hassan was buried near Hariri in Beirut's central Martyrs Square, where thousands of people gathered earlier Sunday for the funeral. TV footage showed al-Hassan's wife Anna, his young sons Majd and Mazen, and his parents shedding tears near his coffin.
There were significant parallels between the life and death of Hariri and al-Hassan - both powerful Sunni figures struck down by car bombs at a time when they were seen to be opposing Syria. Syria denies any role in either killing.
Hariri's death sparked massive street protests in Lebanon that forced Damascus to withdraw its tens of thousands of troops from the country. Al-Hassan's killing, seven years later, has not had such a galvanizing effect: Turnout at his funeral fell well short of expectations, suggesting the country's anti-Syria bloc is rudderless.
Friday's killing also exacerbated sectarian tensions, which already were enflamed over the crisis in Syria. Many of Lebanon's Sunni Muslims have backed Syria's mainly Sunni rebels, while Shiite Muslims have tended to back Syrian President Bashar Assad's regime.
French Foreign Minister Laurent Fabius said it was likely that Assad's government had a hand in Friday's assassination. Fabius told Europe-1 radio that while it was not fully clear who was behind the attack, it was "probable" that Syria played a role.
"Everything suggests that it's an extension of the Syrian tragedy," he said.
Security officials have said seven others were killed in the car bomb, including al-Hassan's bodyguard. But Lebanon's National News Agency said on Sunday that the final toll death toll was three: al-Hassan, his bodyguard and a civilian woman.
The discrepancy could not immediately be explained, though authorities said earlier that the death toll was determined based on body parts found at the blast site.
Al-Hassan knew his life was in danger because of his position as head of the intelligence division of Lebanon's domestic security forces, a role he took over in 2006. Mindful of the country's history of political assassinations, he moved his family to Paris.
A highly secretive man who traveled under tight security, few Lebanese even knew what he looked like until recent years. He was believed to keep a room at police headquarters to limit his travel through the streets of Beirut.
In the wake of Friday's killing, dozens of anti-Syria protesters erected tents in central Beirut, saying they would not leave until Lebanese Prime Minister Najib Mikati's government resigns. Mikati's government is dominated by Hezbollah and its allies.
"The Syrian regime started a war against us and we will fight this battle until the end," said Anthony Labaki, a 24-year-old physiotherapist.
On Sunday, thousands of people mourned al-Hassan in a subdued gathering in downtown Beirut.
But the mood quickly changed: A Sunni cleric, Osama Rifai, gave a fiery speech, telling the crowd to "take out their swords" and not "be like women." Lebanese journalist Nadim Qutaish also called on mourners to "storm the government headquarters!"
The comments were carried live on TV, and more than 1,000 people marched the quarter mile from the funeral site to the stately, hilltop government palace. Several hundred clashed with security forces, first tearing down metal barricades and hitting the guards with the sticks from their flags and placards.
After about an hour of clashes, more guards arrived, along with scores of commandos in helmets and camouflage, carrying long sticks. Standing shoulder to shoulder across the road, they blocked the protesters from advancing further.
"Lebanon is in the eye of the storm," said Fawaz A. Gerges, head of the Middle East Center at the London School of Economics. "The fact that the protesters came close to storming the parliament shows how deep the crisis of the state is and how weak the leadership has become."
Prime Minister Mikati has said he offered to resign after the bombing, but President Michel Suleiman asked him to stay to prevent a power vacuum.
State Minister Ahmad Karami, a close aide to Mikati, told Lebanon's LBC TV that the prime minister "is not clinging to the post, but he will not resign under pressure or for the sake of chaos taking place in the country."
In Washington, State Department spokeswoman Victoria Nuland said the U.S. notes "the importance of political leaders working together at this sensitive time to ensure that calm prevails and that those responsible for the attack are brought to justice."
Unrest also broke out elsewhere in Lebanon. Protesters blocked major roads in Beirut and in the north with rows of burning tires, and briefly closed the country's main highway to the south, the national news agency said.
Clashes erupted in the northern city of Tripoli, with residents of two neighborhoods that support opposite sides in Syria's civil war exchanging gunfire.
Syria's three-decade hold on Lebanon began to slip in 2005, after Hariri's assassination. Still, for years after Syrian troops pulled out, there were attacks on anti-Syrian figures in Lebanon without any trials for those responsible. Assad has managed to maintain his influence through Hezbollah and other allies.
That's what made al-Hassan's recent investigations so extraordinary.
Al-Hassan's work led to the arrest of Samaha, who is accused of plotting a wave of attacks in Lebanon at Syria's behest. The case was an embarrassing blow to Syria - which has long acted with impunity in Lebanon.
Syrian Brig. Gen. Ali Mamlouk, one of Assad's most senior aides, was indicted in absentia in the August sweep.
As the flag-draped coffins of al-Hassan and his bodyguard were carried through Beirut on Sunday, some Lebanese said they wanted to show defiance in the face of so much terror.
"We came for Lebanon's future," said mourner Rama Fakhouri, an interior designer. "And to show that we will not be scared."
This program aired on October 21, 2012. The audio for this program is not available.