The United States imposed sanctions on Friday on Gebran Bassil, the leader of Lebanon's biggest Christian political bloc and son-in-law of President Michel Aoun, accusing him of corruption and ties to Hezbollah.
Bassil, a former foreign minister, heads the Free Patriotic Movement, founded by Aoun.
The sanctions could complicate efforts by Prime Minister-designate Saad al-Hariri, who is trying to navigate Lebanon's sectarian politics to assemble a cabinet to tackle a financial meltdown, Lebanon's worst crisis since its 1975-1990 civil war.