BEIRUT (AFP) - Hundreds of thousands of people crowded central Beirut on Saturday to mark the fourth anniversary of ex-premier Rafiq Hariri's killing in a rally seen as a political litmus test ahead of legislative polls. Waving Lebanese and party flags as well as photos of the slain leader, men, women and children gathered in a festive mood in Martyr's Square as convoys of cars and buses lined roads leading to the capital. "We have come to makes our voices heard," said Khaled Omar, 19. "We want justice and we want the United Nations to watch us today." Joseph Saleh, also 19, said he had travelled from the northern town of Batroun to express his backing for the majority alliance. "We will be the winners of the elections and in the end the truth will prevail," he said. Security was tight in and around the capital with army troops deployed heavily to avoid violence. The rally comes as final preparations are underway in The Hague for the launch of the international tribunal set up to bring Hariri's killers to justice. It also comes as the country prepares for legislative elections in June that will pit the Western-backed parliamentary majority headed by Hariri's son and political heir, Saad Hariri, against a Hezbollah-led alliance backed by Syria and Iran. Saturday's rally is viewed as an indicator of the voters' mood ahead of the polls on June 7. "The size of the crowd is an indicator of the results of the upcoming vote," MP Moustapha Allouch, a member of the majority alliance, told AFP. Several members of the majority, including Saad Hariri, were to address the crowd. Pre-recorded messages from Hariri's widow, Naziq, as well as former French president Jacques Chirac, who was a personal friend of the billionaire ex-premier, were also broadcast. Hariri died in a massive car bombing on February 14, 2005 that also killed 22 others. The attack on the Beirut seafront was one of the worst acts of political violence to rock Lebanon since the 1975-1990 civil war, and led to the withdrawal of Syrian troops after a 29-year presence. The UN tribunal to try Hariri's alleged killers is due to open its doors on March 1, housed in the former headquarters of the Dutch intelligence service on the outskirts of The Hague. The tribunal will also try those presumed responsible for a series of attacks on other Lebanese political and media figures. Seven suspects have been arrested in connection with Hariri's assassination. Among them are four generals, including the former head of Lebanese state security. The UN probe has also implicated senior officials from Syria but Damascus has strongly denied any connection with Hariri's death. US President Barack Obama and UN chief Ban Ki-moon this week reaffirmed their commitment to efforts to uncover the truth in Hariri's murder. "This sad anniversary comes two weeks before the Special Tribunal for Lebanon begins to function on March 1," Ban said on Friday in a statement, referring to the anniversary of the killing. "The Secretary-General reaffirms the commitment of the United Nations to the Special Tribunal's efforts to uncover the truth, bring those responsible for this horrific crime to justice and end impunity in Lebanon."