waving Lebanese gathered in Beirut's main square Sunday to mark the fifth anniversary of the assassination of former prime minister Rafiq Hariri, a killing that sparked a cascade of political turmoil in the Middle East. As in previous years, tens of thousands of people from across the country took part despite a serious rift within the ranks of the pro-Western ruling coalition, now headed by the slain Hariri's son, the current prime minister. It also comes after Prime Minister Saad Hariri reconciled with neighboring Syria, whom he has openly accused of killing his father in the 2005 truck bombing. The 40-year-old Hariri now heads a unity government that includes Syrian-backed politicians who had been part of the political opposition. Rafiq Hariri had close ties with Western leaders and was credited with helping rebuild Lebanon's capital after the 1975-1990 civil war. In the last few months before his assassination, he had tried to limit Syria's influence over Lebanon, and many accused Syria of involvement in his killing. Syria denies those accusations. His death was followed by the rise of a US-backed alliance that became known as the March 14 coalition, named after a day of massive anti-Syrian protests dubbed the “Cedar Revolution.” The demonstrations eventually led to the withdrawal of Syrian troops from the country, ending a 29-year military presence. An international tribunal based in the Netherlands was set up a year ago to prosecute the killers, but no one has been charged and there are frustrations and concerns that the case is languishing. Two high-level departures from the court in recent weeks have increased the worries of Hariri's backers, but the tribunal's head said during a visit to Beirut this month that the resignations were “normal” and that the investigation is on track. UN Secretary-General Ban Ki-moon reaffirmed the United Nations' commitment to the tribunal's efforts to uncover the truth, “so as to bring those responsible to justice and end impunity in Lebanon,” UN spokesman Martin Nesirky said this week at the world body's New York headquarters. President Barack Obama also assured Hariri in a telephone call that he strongly supports the work of the tribunal, according to Hariri's office. Sunday's rally in Beirut's Martyrs' Square is an attempt by Saad Hariri and his allies to regain some of the political momentum lost after a major rift within its ranks.