Saad Hariri said he was proud his father's legacy lives on
Hundreds of thousands of Lebanese have taken to the streets in Beirut for the fourth anniversary of the assassination of former Prime Minister Rafik Hariri.
People waved red and white Lebanese flags and listened to speeches from political leaders amid tight security.
They are also showing support for a UN tribunal into the killing which starts in early March, correspondents say.
Syria has long been suspected of involvement in the massive truck bomb that killed Mr Hariri and 22 others.
Damascus has always denied it had anything to do with the attack.
But such was the public outcry in Lebanon that followed Mr Hariri's death - and pressure internationally - that Syria was forced to pull out its troops after nearly 30 years of military presence.
The scene in Beirut's main square were reminiscent of the demonstrations that followed Mr Hariri's assassination in 2005, the BBC's Natalia Antelava in Beirut says.
People carried pictures of Mr Hariri, with stickers reading "We won't forget you" on their shoulders.
Pictures of the former prime minister were flashed on giant screens, while a choir sang national songs.
The crowd fell silent at 1300 to mark the exact time Mr Hariri was killed.
Saad Hariri, son of Rafik and leader of Lebanon's pro-Western Sunni parliamentary majority, told our correspondent he was proud that his father's legacy was still able to unite the country.
This year's anniversary holds special significance as it comes two weeks before the UN tribunal in the Hague begins its work to try suspects in the killing, our correspondent says.
No suspects have yet been publicly identified, but those in Saturday's crowd said they hoped the tribunal would provide justice.
"We have come to makes our voices heard," Khaled Omar, 19, told the AFP news agency.
"We want justice and we want the United Nations to watch us today."
Mr Hariri's convoy was driving along Beirut's seafront when it was struck by a truck bomb.
It was thought his support for a 2004 UN resolution demanding that Syrian and other foreign troops withdraw from Lebanon had been the reason for the attack.
His death led to a wave of political assassinations. More recently though the country has been enjoying a period of rare calm.
Saturday's demonstration is also being seen as a test of voters' mood ahead of legislative elections in June that will pit Saad Hariri's majority against a Hezbollah-led alliance backed by Syria and Iran.