BISSAU (Reuters) - Guinea Bissau named its fifth prime minister in a year on Friday as the coup-ridden West African country struggled to end months of political gridlock.

A presidential decree named Umaro Mokhtar Sissoco Embalo - a brigadier general as well as a presidential adviser and minister in previous administrations.

President Jose Mario Vaz had to dissolve the previous government on Monday after the last prime minister, Baciro Dja, failed to win the full support of his ruling PAIGC party, an organization hit by regular infighting.

Political rivals agreed in September to a plan to ease a crisis that has prevented parliament from agreeing budgets and blocked international aid.

The six-point plan, put together with the help of regional mediators, included a preliminary agreement to form a consensus government.

The former Portuguese colony has seen nine coups or attempted coups since 1980 and become a major transit point for cocaine trafficked from South America to Europe.

(Reporting By Alberto Dabo; Writing by Aaron Ross; Editing by Andrew Heavens)