Before this development, Guinea Bissau had two presidents.
Cipriano Cassamá was chosen by lawmakers as president following disputed elections in December.
This was despite the fact that former army general, Umaro Cissoko Embaló had already been sworn in as president at a hotel in the capital, Bissau.
According to BBC, outgoing President José Mário Vaz handed power to Mr Embaló at a ceremony at a luxury hotel on Thursday.
But Mr Pereira’s PAIGC party, which led Guinea-Bissau to independence rejected Mr Embaló’s inauguration, describing the election as marred by fraud.
The party then used its parliamentary majority to swear in Mr Cassamá, the parliamentary speaker, as interim president, until the Supreme Court ruled on its bid to annul Mr Embaló’s victory.
Giving reasons for his resignation, Mr Cassama said he stepped down due to death threats,
He added that his life is in danger, and he has no security.
“I have no security, my life is in danger, the life of my family is in danger, the life of this people is in danger. I cannot accept that, that is why I took this decision”.
Despite the resignation of one president, Guinea-Bissau still has two rival prime ministers.
