"To mark this historic event, a short public ceremony will be held at the STL court building," the tribunal said in a statement.

Officials expected to attend the ceremony include Canadian prosecutor Daniel Bellemare, registrar Robin Vincent, and Patricia O'Brien, the U.N. under secretary general for legal affairs.

The court, known informally as the Hariri tribunal, has existed on paper since June 10, 2007, when it was brought to life by a resolution of the U.N. Security Council.

Eleven judges, including four Lebanese, have been nominated to work at the tribunal, housed at the former headquarters of the Dutch intelligence service in the town of Leidschendam. The judges' names are being kept under wraps for security reasons.

Seven suspects are being held in Lebanon in a probe into a series of attacks on Lebanese political and media personalities, notably Hariri's assassination in a car bombing in February 2005 that also killed 22 others.

German Detlev Mehlis, who preceded Bellemare as head of the international investigation, has previously said there was evidence implicating Syrian and Lebanese intelligence services in Hariri's assassination. Damascus has denied any involvement.

Bellemare has indicated he would seek the transfer of suspects to The Hague within two months of the tribunal's opening.

The court's budget will amount to some $51.4 million in 2009 - 49% of it financed by Lebanon. -AFP