Judge David Re, president of the trial chamber, read the names of the four defendants being tried in absentia and the charges against them as a model of downtown Beirut, where the explosion that killed Hariri and 21 others occurred, was on display in the courtroom, the (Beirut) Daily Star reported.
Hezbollah member Mustafa Badreddine, Salim Ayyash, Assad Sabra and Hussein Oneissi have avoided capture since they were indicted in June by the Special Tribunal for Lebanon in the Feb. 14, 2005, assassination.
A fifth Hezbollah suspect, Hassan Merhi, was accused of complicity in the killing but the tribunal has yet to decide whether he would be tried with the others, the Daily Star said.
In his opening statements, Prosecutor Norman Farrell called the assassination as an attack that "captured the attention of the world."
He said evidence would show Hariri was tracked by a sophisticated and complex surveillance plan and the suspects worked to conceal their identities and create a false trail to mislead investigators.
The attack was aimed at sending "a terrifying message and to cause panic among the population of Beirut and Lebanon."
Several victims and families attended the trial's opening, including former Lebanese Prime Minister Saad Hariri, the son of Rafik Hariri, and several lawmakers, the Daily Star reported.
"The start of the trial is a historic day that opens a new page for justice in Lebanon," Saad Hariri said on the eve of the trial.