An army general has been sworn in as Guinea-Bissau's new head of state a day after an apparent coup.

Gen Horta N'Tam becomes the transitional president for a period of one year. He took the oath on Thursday, in brief and muted proceedings in the army headquarters.

The military had already suspended the electoral process and blocked the release of the results of Sunday's presidential election, which were expected on Thursday.

Some civil society groups in Guinea-Bissau have accused outgoing President Umaro Sissoco Embaló of masterminding a simulated coup against himself with the help of the military, saying it was a ruse to block election results from coming out in case he loses.

The Popular Front coalition stated that this manoeuvre aims to prevent the publication of the electoral results scheduled for November 27. The president has not responded to the allegations.

Embalo claims to have survived multiple coup attempts but has been accused by critics of fabricating crises to suppress opposition.

Sandwiched between Senegal and Guinea, Guinea-Bissau is notorious for drug trafficking and has seen at least nine coups or attempted coups since gaining independence from Portugal in 1974.

The latest coup announcement came following reports that President Embaló had been arrested. Military officers stated they suspended the electoral process to thwart a plot allegedly involving a well-known drug baron and announced the closure of borders and a night-time curfew.

As of Thursday, reports indicated that Guinea-Bissau's borders had reopened, but the political landscape remains fraught with uncertainty as both Embaló and his main rival, Fernando Dias, claimed victory in the now-stalled elections.

The situation has drawn concern from international observers and Portugal, the country’s former colonial power, which called for a return to constitutional order and restraint from all parties involved.