The Hague  - The international tribunal to try suspects in the assassination of former Lebanese prime minister Rafik Hariri four years ago was formally constituted in The Hague Sunday.

The court, constituted under a United Nations mandate, is to probe among other things allegations that Syria was behind the killing of Hariri in a massive Beirut bomb blast on 14 February 2005.

Syria has repeatedly denied allegations of involvement in the Hariri attack, in which 22 other people were also killed.

Court registrar Robin Vincent told the opening that the tribunal was in the first place not so much for the United Nations or for the international community as "for Lebanon".

A group of several dozen Lebanese outside the heavily-fortified tribunal building - a former Dutch secret service gym in The Hague suburb of Leidschendam-Voorburg - waved national flags.

They also held aloft banners proclaiming "thank you, Holland" - a reference to the Dutch government making the facility available for the tribunal to go ahead on neutral territory.

Four Lebanese generals regarded as pro-Syrian are expected to be charged by The Hague court in connection with the murder. A Lebanese investigating judge Friday rejected a request for their release.

The four - Mustafa Hamdan, commander of the presidential guard, Jamil Sayyed, director of security services, domestic security head Ali Hajj, and the commander of army intelligence Raymond Azar - have been detained in Lebanon since 2005.

Canadian Daniel Bellemare assumed the role of the tribunal's chief prosecutor. The 56-year-old had been the head UN investigator in the case since November 2007.

Bellemere pledged to do all in his power to get to the bottom of the assassination, and had already made clear before Sunday's formal opening of the tribunal that he would seek the transfer of the four generals from Lebanon.

The four have not been formally charged. Bellemere has 60 days to apply to the Lebanese authorities for the transfer of suspects and evidence files.

The tribunal's hearings are expected to last for several years, and it is expected that months will pass before anyone actually goes on trial.

The tribunal will operate under Lebanese law - but without the death penalty - with an international panel of 11 judges and a staff of 300 under an initial mandate of three years. The highest sentence it will be able to impose will be life imprisonment.

It is financed to 49 per cent by the Lebanese government and 51 per cent by donor nations including the United States and Germany - to the tune of 40 million euros for the first year, financing which has already been guaranteed.

With Lebanese society still polarized into pro- and anti- Syrian camps, and having just emerged from an 18-month political stalemate, the tribunal is likely to aggravate wounds that have hardly healed.

Observers fear it will derail upcoming parliamentary elections on June 7 - a heated race between the western-backed ruling majority and the opposition led by Hezbollah, backed by Syria and Iran.

The two sides are opposed on whether the tribunal should even exist in the first place, and some observers believe it might lead to conflicts in the streets similar to the ones witnessed during May 2008, when 82 people were killed in clashes.

The opposition have long claimed that the tribunal constitutes an unacceptable violation of Lebanese sovereignty - even though it will operate under the Lebanese criminal code - and that it can be politicized to serve as a tool against Syria, their main ally.

In comments made last week to the Lebanese media, Bellemare tried to assure all factions involved that the tribunal would not be a "political exercise" but "a legal process driven by legal rules."

Previous UN reports, including one written by German prosecutor Detlev Mehlis, have implicated the Syrian intelligence establishment in the killing.

One version of Mehlis' 2005 report even leaked the names of senior Syrian officials, including the brother and brother- in-law of President Bashar al-Assad.

Assad has however long denied any involvement in Hariri's killing and has said Syria will not allow its citizens to appear before the tribunal. dpa