BOGOTA, Colombia  

Haiti’s Senate designated Joseph Lambert, the head of the upper house of Congress, as interim president on Friday after the assassination of Jovenel Moise earlier this week.

Lambert's grip on power plunges the country into a state of extreme political uncertainty.

The move undermines the authority of Prime Minister Claude Joseph, who declared himself the leader with US and UN support.

Joseph requested the UN and the US send troops to help secure the nation´s port, airport and other strategic infrastructure after Moise was killed on Wednesday by a commando of 28 gunmen.

Eight senators who signed the resolution considered that Joseph was removed from office on Monday in the last decree signed by Moise before his assassination. The president appointed Ariel Henry to succeed Joseph.

"Claude Joseph is not the prime minister. He is part of my government," Henry told the media.

Lambert will take over as head of state until Feb. 7, 2022, when Moise's mandate ends, and his first task will be to organize elections, according to the resolution.

But many are questioning whether the Senate has the power to designate a president.

The Senate has 10 sitting lawmakers and it has not been allowed to make decisions because of a lack of a quorum.

Both the Chamber of Deputies, or lower house, and two-thirds of the Senate were scheduled to be renewed in 2019, but the elections were postponed due to political instability. Congress was closed, causing Moise to rule by decree for more than a year.