US Vice-President Joe Biden has arrived in Beirut in what the US calls a show of support for Lebanese independence ahead of crunch legislative elections, BBC reported.
The vote in two weeks could see the militant and political Shia movement Hezbollah gain a parliament majority.
A top Hezbollah official called the visit an example of US "meddling" to shore up support for the pro-western faction "which feels under threat".
Mr Biden is due to announce fresh US military aid to the Lebanese military.