UN chief Ban Ki-Moon, who has raised fears that Lebanon could be dragged into Syria's civil war, called on the Lebanese to unite after the resignation of Prime Minister Najib Mikati.
Ban also called on Lebanese parties to maintain their policy of "disassociation" from the Syrian conflict, UN spokesman Martin Nesirky said in a statement released late Friday.
"At this challenging time for the region, the secretary general calls on all the parties in Lebanon to remain united behind the leadership of President (Michel) Sleiman," said the statement.
"He also calls on them to work together with the institutions of the state to maintain calm and stability, to respect Lebanon's policy of disassociation."
Ban said Lebanese parties must "support the role of the Lebanese armed forces in sustaining national unity, sovereignty and security."
Mikati formally submitted his resignation on Saturday as his government battled deep divisions over the two-year-old war in neighboring Syria, which has divided the Lebanese along sectarian fault lines.