Lawyers for the four men indicted by the U.N.-backed Special Tribunal for Lebanon say the court has no right to exist and should dissolve itself.
Lawyer Emile Aoun told judges at the tribunal on Wednesday that the U.N. Security Council resolution that created the court was an illegal violation of Lebanon's sovereignty. Aoun is defending the absent suspect Salim Ayyash.
The tribunal was set up to investigate the 2005 assassination of Lebanese Prime Minister Rafik Hariri in a bomb blast that also killed 22 others.
The court has indicted four members of the Shiite Muslim Hezbollah group which, along with its allies, now holds a majority in Lebanon's Cabinet. Hezbollah denies involvement in Hariri's killing and has refused to extradite the suspects.