Lebanese political leaders and supporters of the March 14 movement are due to participate in a commemoration ceremony in Beirut to mark 10 years since the assassination of former Prime Minister Rafik al-Hariri.
On February 14, 2005, Hariri along with 22 others were killed in massive explosion on Beirut's waterfront shortly after leaving a parliament session.
Hariri's son, former Prime Minister Saad al-Hariri, made a rare visit to Lebanon on Saturday to speak at the commemoration of his father's assassination, Lebanese media said.
Saad al-Hariri, Lebanon's most influential Sunni politician, left the country in 2011 after his government was toppled by a coalition including the Shia group Hezbollah.
He splits his time between Saudi Arabia and France.
The killing of Rafik al-Hariri threw Lebanon into a new phase of political turmoil, and plunged the country into its worst political crisis since the end of the 1975-1990 civil war.
Five followers of Hezbollah - Salim Jamil Ayyash, Mustafa Amine Badreddine, Hussein Hassan Oneissi, Assad Hassan Sabra and Hassan Habibi Merhi - have been indicted over the killing of Hariri in the special tribunal for Lebanon.
They remain at large and are being tried in absentia.
A memorial monument on the site of Hariri's assassination was set up, and a statue of him was built nearby with a sign reading the names of all those killed in February 2005 blast in Beirut's waterfront near Saint-Georges hotel.
The Lebanon tribunal, which was set up in 2009 at the urging of Western governments, initially enjoyed the support of the then Lebanese government, but Lebanese attitudes towards its investigation have since become more lukewarm.
Some citizens still hope the tribunal will bring justice and put Lebanon back on track in its political and security situation, while others are less optimistic.
Hariri's assassination was followed by a series of attacks which killed anti-Syrian politicians, officials and journalists.