The United States and some of its European allies last week warned their citizens to avoid traveling to Lebanon because of heightened tensions associated with civil war in neighboring Syria.
Western allies are considering military intervention in Syria in response to the alleged use of chemical weapons by government forces last month.
Lebanon freed itself from Syrian dominance by revolution in 2005, though the fighting in Syria threatens to spill over their common border.
The International News Safety Institute said Monday it was advising journalists working in Lebanon to maintain a low profile.
Some of the southern suburbs of Beirut are considered Hezbollah territory. Following a series of bombings in the capital, a journalist working in Lebanon told INSI on condition of anonymity "the rules of the game" have changed.
"There's a perception that there may well be another attack in Beirut," the source said.
Hezbollah admitted early this year to fighting alongside government forces in Syria. Some of the violence in Lebanon was seen by officials there as a reaction to the Shiite movement's role in Syria's civil war.