Lebanon is observing the first of three days of mourning in memory of Pierre Gemayel, the Maronite Christian politician assassinated in Beirut.
Pierre Gemayel was one of a young generation of politicians
Mr Gemayel, 34, was shot in his car in a Christian area of the city.
The head of the anti-Syrian coalition, Saad Hariri, blamed Damascus. Syria has strongly denied any involvement.
World leaders have condemned the cabinet minister's killing, and the UN Security Council has criticised attempts to destabilise the country.
The army took to the streets of Beirut after the attack. Tyres were burned in the Christian neighbourhood of Ashrafiyeh.
Anti-Syrian protesters also shouted slogans and blocked streets in the Christian town of Zahle in east Lebanon.
BBC Middle East correspondent Jeremy Bowen says the assassination seems to have been designed to inflame sectarian tensions at a time when Lebanon was already going through a profound political crisis.
Last week, Lebanon's cabinet endorsed plans to set up a tribunal to try those suspected of killing former Prime Minister Rafik Hariri - Saad Hariri's father - despite the resignations of six pro-Syrian ministers opposed to it.
A UN report recently implicated Damascus in the killing of Hariri by a truck bomb in Beirut in February 2005. Syria denies the charges.
The Security Council approved the plans for the tribunal on Tuesday. The Lebanese government will now be asked to approve it formally.
Mr Gemayel, minister for industry, was a member of the Phalange Party and the son of former President Amin Gemayel.
Speaking to crowds of angry supporters outside the hospital where his son was pronounced dead, the former president called his son a martyr and asked for a peaceful reaction.
"We don't want reactions and revenge," he said.
At least three gunmen ambushed Mr Gemayel, ramming his car with their vehicle before spraying it with gunfire from point blank range.
The killing brought a swift reaction from world leaders, many of whom also offered backing for the government of Prime Minister Fouad Siniora.
Mr Siniora said assassinations would not terrorise Lebanon, adding: "We will not let the criminal killers control our fate."
US President George W Bush called for a full investigation to identify "those people and those forces" behind the killing.
Mr Bush backed Mr Siniora's government, accusing Syria and Iran of fomenting "instability and violence" in Lebanon.
"Syria's refusal to cease and desist from its continuing efforts to destabilise Lebanon's democratically elected government is a repeated violation of United Nations Security Council resolutions," he said.
UK Prime Minister Tony Blair said the killing was "completely without any justification at all", while Syria called it a "despicable crime".
There was also condemnation of the killing from Iran and from the Hezbollah, the Shia Muslim Lebanese political and militant group.
Tehran called the killing an attack by "Lebanon's enemies", while Hezbollah called for a swift investigation.