The United States authorized non-essential personnel and their families to leave their embassy near Beirut on Tuesday, citing the unpredictable security situation in Lebanon due to the Israel-Hamas war.
The State Department also raised its travel advisory for Lebanon from level three, issued in July, to the highest available level four, as it told Americans to avoid the country.
"Do not travel to Lebanon due to the unpredictable security situation related to rocket, missile, and artillery exchanges between Israel and Hezbollah or other armed militant factions," the State Department said in a statement Tuesday.
Hamas launched a massive assault against Israel on October 7, shooting, stabbing and burning to death more than 1,400 people, most of them civilians.
Reeling from the worst attack in its history, Israel launched a wave of retaliatory air strikes against the Gaza Strip, killing about 3,000 people, mostly civilians.
Lebanon-based Hezbollah, which like Hamas is backed by Iran, has since been involved in a series of tit-for-tat incidents along the south Lebanese border with Israel.
After a blast ripped through a Gaza hospital on Tuesday, killing hundreds, Hezbollah called for a "day of rage."
Israel and Palestinians have traded blame for the blast, though neither's claim could be independently verified.
Following Hezbollah's call, hundreds of demonstrators scuffled Tuesday night with Lebanese security forces outside the US embassy in the Beirut suburb of Awkar, where protesters hurled stones and set a building on fire, according to AFP correspondents.
Hundreds also gathered at the French embassy in Beirut, raising Hezbollah flags and also hurling stones which piled up at the embassy's main entrance.
Palestinian refugee camps in the southern cities of Sidon and Tyre erupted in anger as Palestinian factions in Lebanon called for mass rallies on Wednesday to condemn the hospital strike.
Since October 7, fire along the Israel-Lebanon border has killed at least 18 people on the Lebanese side -- mostly fighters, but also a Reuters journalist and two civilians.
At least three people have been killed on the Israeli side.
France has also urged its citizens to avoid travel to Lebanon, while several Western airlines have suspended flights.
Britain's foreign office has told its nationals in Lebanon to "consider whether you need to remain and, if not, leave by commercial means while they are still available."
Canada, Spain, Germany and Australia have also issued travel warnings.