No injuries were reported when four rockets fired from Syrian territory struck southern Lebanon last weekend. Lebanese President Michel Suleiman said Monday he was surprised by the assault on national security.
A statement from his office, published by The Daily Star newspaper, said it was part of an ongoing effort to push Lebanon into a state of disarray.
"[Suleiman] ordered the Lebanese army to determine the source of fire and deal with it with the appropriate means," the statement said.
Lebanon has been on edge for most of the year as the Syrian civil war threatens to spill over the border. Internal dynamics were strained when Hezbollah admitted it had fighters fighting alongside pro-government forces in Syria.
More than 20 people were killed and at least 250 others were injured when a bomb exploded last week in a Hezbollah stronghold in southern Beirut.
The bombing followed a statement from Hezbollah Secretary-General Hassan Nasrallah taking credit for an explosion that injured four Israeli troops along the southern border.