Secretary-General Ban Ki-moon expressed serious concern Thursday at the Lebanese parliament's failure to authorize an international tribunal to prosecute suspects in the assassination of former prime minister Rafik Hariri, and again urged the government to take action. Ban said he discussed the problem Wednesday during a phone conversation with Prime Minister Fuad Saniora and had received letters from members of Lebanon's parliament seeking UN action. Saniora sent a letter to Ban on Tuesday asking the UN Security Council to authorize the tribunal because of "unjustified difficulties" that are hampering the process of ratifying the tribunal in Lebanon. He accused the country's pro-Syrian Parliament Speaker Nabih Berri of "paralyzing" the assembly because he refused to convene a session to ratify the tribunal. Last week, 70 of parliament's 128 members signed a memorandum demanding UN action to establish the tribunal.