Holding aloft red roses and Lebanese flags, the throngs on the streets shouted insults directed at Syria and demanded the resignation of the pro-Syrian government in a march that began at the seaside site where Hariri and 16 others were killed and ended at his grave in the city center.
The protesters wore scarves of red and white -- the colors of Lebanon's flag -- which have become the symbol of the opposition's independence uprising, described as a peaceful campaign to dislodge the government and force the Syrian Army out of Lebanon.
Hariri's assassination has brought Lebanese together and strengthened the opposition, but it was unclear if the momentum would force a change in government or push the Syrian Army out of the country.
Another former prime minister, General Michel Aoun, said yesterday he would return from exile before this year's parliamentary elections and that he may launch his own candidacy if the opposition needs his support. The former commander of the Lebanese Army fled the country in 1990.
''I will return before the legislative elections, probably by mid-April," Aoun said in a telephone interview from Paris. ''And if the situation is critical for the opposition in a region, then I will throw in my personal weight and run in the elections."
As the demonstration was under way in Beirut, Bush issued a strong warning to Syria from Brussels, saying Damascus ''must end its occupation of Lebanon."
In Damascus, Arab League Secretary-General Amr Moussa said Syria's president, Bashar Assad, affirmed during a meeting that his country will soon take steps to withdraw its army from Lebanese areas in line with a 1989 agreement. It was not clear whether that meant Syria would completely leave Lebanon.
Syria, which sent its army into Lebanon in 1976 amid the civil war, has always pledged to implement the 1989 accord that ended the conflict, and has redeployed troops several times since 2000. However, a withdrawal to the eastern Bekaa Valley near the border that was scheduled for the early 1990s, followed by an eventual total pullout, has never been carried out.
Syrian troops here once numbered 35,000; the current number is 15,000, and Syria remains the chief power broker in Lebanon.