BISSAU (Reuters) - Guinea-Bissau's sacked prime minister, Carlos Correia, denounced the dismissal of his government by President Jose Mario Vaz as a "constitutional coup d'etat" on Friday, as a new premier was sworn in.
Opponents of Vaz protested outside his presidential palace on Thursday night, burning tyres and throwing rocks, after he named Baciro Dja as the new prime minister.
Vaz sacked Correia and his government on May 12, saying they had proved incapable of managing a months-long political crisis. The ruling PAIGC party has been embroiled in a power struggle since last summer, caused partly by the overlapping duties of the president and prime minister in a semi-presidential system.
"We are facing a constitutional coup d'etat because the dismissal of my government is unconstitutional," Correia told Reuters.
Members of Correia's government were still at their offices on Friday and he said they will not transfer their duties to ministers named by Dja.
The PAIGC said in a statement it would not support the new prime minister, who was sworn in on Friday.
It is the second time Vaz has named Dja to head the government, having appointed him last August after sacking his own main rival in the PAIGC.
But Dja was forced to step down after the Supreme Court ruled his appointment violated the constitution.
Dja now has the task of forming Guinea-Bissau's fourth government in 10 months.
A spokesman for Secretary-General Ban Ki-moon said the United Nations chief was "deeply concerned" by the situation following Dja's nomination and the subsequent protests.
"He urges all political stakeholders and their supporters to act responsibly, refrain from violence and avoid an escalation of the situation by settling their concerns through dialogue," the spokesman said in a statement.
The former Portuguese colony is notoriously unstable and has seen nine coups or attempted coups since 1980.
Vaz, a former finance minister, was elected in 2014 after the army was forced to hand back power to civilian politicians following a military coup.
Since independence in 1974, no democratically elected leader has served a full term in Guinea-Bissau. The political turbulence has helped it become a major transit point for cocaine trafficked from South America to Europe.
(Reporting by Alberto Dabo; Writing by Makini Brice; Editing by Joe Bavier and Angus MacSwan)