- Son of slain premier Hariri says start of trial "a day for Lebanon"
- Four suspects are being tried in absentia in The Hague
- The 2005 assassination polarized Lebanon and led to the withdrawal of Syrian troops
- Earlier, a bomb killed three people and injured 26 in the city of Hermel in northeast Lebanon
Nine years after the assassination of former Prime Minister Rafik Hariri, a seismic event in Lebanese history, the trial of four men accused of his killing opened Thursday in a special United Nations-backed court.
However, the stand at the Special Tribunal for Lebanon in The Hague was empty, with the suspects -- alleged associates of the Shiite militant group Hezbollah -- still on the run.
Billionaire statesman Hariri was killed in February 2005 when a bomb struck his motorcade near the Beirut seafront. The blast ripped apart his armored car and destroyed the motorcade, killing 21 other people and wounding more than 200 others.
It was a moment that changed Lebanese history, fueling the sectarian divisions between Sunni and Shiite Muslims in the Mediterranean country and leading to the withdrawal of Syrian troops.
The special court investigating the assassination announced in February 2012 that Mustafa Badreddine, Salim Ayyash, Hussein Oneissi and Assad Sabra would be tried in absentia.
They face counts ranging from conspiracy to commit a terrorist act to murder and attempted murder. Hezbollah denies involvement.
Hearing streamed live
Presiding Judge David Re opened the trial, presenting the indictments against the accused. Thursday's hearing also included the prosecution's opening statements, expected to continue until Friday, according to the official Twitter account of the Special Tribunal for Lebanon.
"This is a historic day for the Special Tribunal for Lebanon as it marks the transition from complex and difficult investigations to the new phase of trial," said Marten Youssef, a spokesman for the tribunal.
The hearing is being streamed live online. In Lebanon, television stations -- except for Hezbollah's Al Manar -- broadcast it live.
"A day for Lebanon"
Youssef said the case was the "first trial for a crime of terrorism in an international tribunal." It is being held in Leidschendam, on the outskirts of The Hague.
Hariri's son Saad, also a former prime minister, and other family members have traveled to the city.
Speaking outside the court building, Saad Hariri thanked the Special Tribunal for Lebanon "for the opportunity to find justice against the criminals who committed this heinous crime."
"Unfortunately the names of those who perpetrated these crimes are Lebanese, they follow a certain political party," he said. "They are innocent until proven guilty. This is what we want ... justice, not vengeance. We never seek vengeance and hopefully by the end of this trial we will find out the truth and we will get the justice that we called for in Lebanon."
He said the start of the trial was "a day for Lebanon; today is a day we fought for nine years."
Hariri's supporters say the businessman-turned-politician was killed because of his opposition to Syria's longtime military presence in his country, and his death led to popular protests, nicknamed the "Cedar Revolution," that led Damascus to withdraw its troops.
Syrian troops were deployed in Lebanon between 1976 and 2005, primarily in the north -- ostensibly at first as peacekeepers to help stop Lebanon's long civil war -- but maintained a significant presence long after the fighting stopped in 1990.
Syria has denied accusations that it was behind the bombing.
Shortly before the trial began, a bomb blast ripped through the northeastern Lebanese city of Hermel, killing three people and injuring 26 others, state news agency NNA reported.
The explosion took place near city offices and a number of banks.
Hermel is in the northern Bekaa Valley near the Syrian border and is known as a Hezbollah stronghold.
NNA said a suicide bomber had blown up a car, and the army said expert teams were investigating the site.
"Army units in the region deployed and cordoned off the area, and a unit of the military police and a number of specialized experts came to the scene to investigate the site ... and remains found next to the car to specify the nature of the blast," the military said in a statement.
Thursday's bombing was the latest in a wave of attacks to hit Lebanon in recent months as the civil war in Syria increasingly spills over the border into its smaller neighbor.
Hermel has been targeted before, with missiles launched from Syria, where Hezbollah has sent fighters and military advisers.