Former minister Hassan Diab became Lebanon's new prime minister on Thursday (December 19) with backing from the Iran-backed group Hezbollah and its allies.
The country has been crippled by the worst economic crisis since the 1975-90 civil war and has been in dire need of a new government since the then prime minister Saad al-Hariri resigned at the end of October.
Violent protests against the ruling elite followed.
Diab, an engineer and academic, taking the helm could seriously complicate Lebanon's efforts to secure badly needed Western financial aid because Hezbollah is under U.S. sanctions and listed as a terrorist group by Washington.
Hariri - who is aligned with the West and Gulf Arab states - had been expected to be nominated.
But he took himself out of the running on Wednesday (December 18) night.
He still participated in the formal consultations at the presidential palace.
The new government will face unprecedented financial issues.
Banks are imposing tight capital controls, the Lebanese pound has slumped by a third from its official rate and companies are slashing jobs and salaries.