LEIDSCHENDAM, Netherlands - Four Hezbollah members went on trial in absentia at a special UN tribunal on Thursday accused of murdering Lebanon’s former premier Rafiq Hariri in a 2005 car bombing that shook the Middle East.

The trial opened in a suburb of The Hague nine years after the huge Beirut blast that killed billionaire Hariri and just hours after another deadly car bombing in a Hezbollah stronghold near war-ravaged Syria. A packed public gallery looked on as the repeatedly-delayed proceedings began, with a large scale model of downtown Beirut where the 2005 attack happened on a table set up before judges. Hariri’s son Saad - who himself was prime minister 2009-2011 - sat in the courtroom behind the victims’ representative. Dressed in a dark suit, his hands were folded as he listened attentively.

The Special Tribunal for Lebanon (STL) is unique in international justice as it was set up to try the perpetrators of a terrorist attack and because it can try the suspects in absentia. Hariri, Lebanon’s Sunni prime minister until his resignation in October 2004, was on his way home for lunch when a suicide bomber detonated a van full of explosives equivalent to 2.5 tonnes of TNT as his armoured convoy passed.

The February 14, 2005 seafront blast killed 22 people including Damascus opponent Hariri and wounded 226, leading to the establishment by the UN Security Council of the STL in 2007.

Prosecutors will aim to prove the accused men’s involvement through tracking their alleged use of mobile phones before, during and after the attack.

Meanwhile, a likely suicide car bomb Thursday ripped through the main square of Hermel, a Hezbollah bastion in Lebanon’s Bekaa Valley, killing three people in the latest attack linked to Syria’s war.

The bomb, which exploded in front of Hermel’s main government building, was the first to hit the town since the Syrian conflict erupted in March 2011, a security official told AFP. It was the fifth major assault on a Hezbollah stronghold in Lebanon since the movement admitted it was fighting alongside President Bashar al-Assad’s forces in Syria.

Health Minister Ali Hassan Khalil said three people were killed and 31 wounded in the town located only about 10 kilometres (six miles) from the Syrian border.

“Two of the bodies were unidentified. We don’t know whether one of them was a suicide attacker,” Khalil told Hezbollah’s Al-Manar television channel.

The bombing came amid raging tensions in Lebanon mainly over the war in neighbouring Syria, where Hezbollah has been openly involved in the fighting for eight months.

“At around 8:55 am (0655 GMT) a car bomb exploded in front of the government administration building in Hermel,” the army said.

Interior Minister Marwan Charbel said that “given the human remains in the car and next to it, it seems like a suicide attack, but we will not rush to judgement”.

The attack damaged buildings around Hermel’s main square.

“The explosion was huge. People are really scared and upset. It took place just as people were on their way to work and to go about their daily business in the middle of town,” said Ali Shamas, the headmaster of a Hermel college.

“There was a lot of smoke rising from the scene.”

An AFP photographer saw body parts strewn on the ground, as well as damaged vehicles and ambulances transporting casualties away.

The army cordoned off the affected buildings as investigations were launched.

The government building in the Hermel square houses the town’s main administrative offices as well as police and security posts.

President Michel Sleiman described the attack as “the latest in a criminal series that target Lebanon’s stability.”

“Immunising (Lebanon) from such terrorist groups will require solidarity between leaders and the people, and the rapid establishment of a government that is able to meet the challenges,” he said.

For nine months, Lebanon’s rival political camps have failed to form a government.

Hermel has been hit in recent months by mortar attacks launched from neighbouring Syria.

Hezbollah has since last May been openly involved in Syria’s war, sending in thousands of fighters to support forces loyal to President Assad.

But Hezbollah MP Nawar al-Sahili said: “What happens in Syria stays in Syria... There must be no links made between our presence in Syria and these terrorist, criminal, cowardly explosions.”

Five major attacks have struck Hezbollah bastions in southern Beirut and in eastern Lebanon since it admitted it is fighting on Assad’s side.

Prior to Thursday’s attack, the two most recent were claimed by the Abdallah Azzam Brigades, which is loyal to Al-Qaeda.

Its leader Majid al-Majid died of poor health this month, but the brigades later warned of new attacks targeting Hezbollah and its backer Iran.

Until 2005, Lebanon had been dominated politically and militarily by Syria for 30 years.

It is still sharply divided into pro- and anti-Damascus camps, and the Syrian conflict has compounded Lebanon’s sectarian and political divisions.

While Lebanon has suffered a spike in violence since the war in Syria broke out, the frequency of attacks has risen in recent weeks.

In November, 25 people were killed in a twin suicide attack targeting the Iranian embassy in southern Beirut, also a Hezbollah bastion.

Then in late December, eight people were killed in a car bomb attack targeting a former minister opposed to Assad.

And on January 2, a suicide blast tore through southern Beirut, killing five people.