Lebanon's president has appointed parliamentary majority leader Saad al-Hariri prime minister-designate
President Michel Suleiman issued a presidential decree designating Sunni Muslim Hariri after 86 parliamentarians in the 128-seat assembly nominated him for the post.
Mr Hariri said he would seek to form a unity government capable of facing the country's many political, economic and social challenges, though he warned the task would be difficult.
Mr Hariri, who is backed by the United States and Saudi Arabia, led a political coalition to victory against Iranian-backed Hezbollah and its allies in this month's election.
He is the son of statesman Rafik al-Hariri whose assassination in 2005 plunged Lebanon into the worst crisis since the 1975-1990 civil war.
Lebanon's sectarian power-sharing system reserves the premiership for a Sunni.
In a sign of the difficulties the 39-year-old leader faces in forming a cabinet acceptable to all sides, Hezbollah and its Christian allies refrained from nominating him.
Only 15 out of the minority alliance's 57 deputies backed him, adding to support from Hariri's 71 deputies.