The US Embassy in Beirut urged American citizens in Lebanon to leave, citing the "complex" security environment that "can change quickly."
"We urge US citizens to depart Lebanon while commercial flight options remain available," the embassy said in a statement.
"We recommend that US citizens in Lebanon who choose not to leave prepare contingency plans for emergency situations and to monitor the news for breaking developments," it added.
"There are ongoing risks of terrorism and kidnapping throughout Lebanon," the mission warned.
Places commonly visited by US citizens and tourists in Beirut and across Lebanon "may become a target for these attacks," the embassy added, calling on US citizens to avoid protests and large gatherings.
The statement came after Wednesday's exchange of fire between the Israeli army and Lebanese group Hezbollah. The escalation came despite a 10-day ceasefire between Lebanon and Israel which commenced Friday.
The truce was intended to halt Israel's expanded attacks on Lebanon, which have killed 2,294 people, wounded 7,544, and displaced more than 1 million since March 2.
The advisory was issued on the eve of US-mediated talks between Lebanon and Israel that are set to be held on Thursday.
