Several countries have urged their nationals to leave Lebanon, as fears grow of a wider conflict in the Middle East.
Iran has vowed “severe” retaliation against Israel, which it blames for the death of Hamas political chief Ismail Haniyeh in Tehran on Wednesday. Israel has not commented.
His assassination came hours after Israel killed Hezbollah senior commander Fuad Shukr in Beirut.
Western officials fear that Hezbollah, an Iran-backed militia and political movement based in Lebanon, could play a key role in any such retaliation, which in turn could spark a serious Israeli response.
Diplomatic efforts by the US and other Western countries continue to try to de-escalate tensions across the region.
A growing number of flights have been canceled or suspended at the country’s only commercial airport in Beirut.