Susuga Malietoa Tanumafili II, 94, one of the world's longest-reigning monarchs, has died, the prime minister's office announced.

King Malietoa died Friday night at Tupua Tamasese National Hospital in the Samoan capital of Apia, where he had been staying for about a week. The cause of death was not announced.

The king succeeded to the title in 1940, when his father died. He was made Samoa's joint head of state with Tupua Tamasese Meaole when the country gained independence from New Zealand in 1962, and he became sole head of state a year later when Tupua Tamasese died.

He was the world's third longest-serving sovereign, after Thailand's King Bhumibol Adulyadej, who has reigned since 1946, and Britain's Queen Elizabeth II, who ascended to the throne in 1952.

King Malietoa's successor will be elected by the Legislative Assembly to a five-year term as stipulated in the Samoan constitution.

In American Samoa, Gov. Togiola T.A. Tulafono offered his condolences to the people of neighboring Samoa on King Malietoa's death. Many American Samoans considered him to be the father of the two Samoas, and he was a frequent visitor to the U.S. territory's annual Flag Day festivities.

Samoa, a group of islands in the South Pacific, is about halfway between Hawaii and New Zealand and is home to 200,000 people.