Tonga's king since 1965 gravely ill in New Zealand

Taufa'ahau Tupou IV, the king of Tonga and one of the world's longest-reigning monarchs, is gravely ill in a New Zealand hospital, the government of the tiny South Pacific nation said.

Prime Minister Feleti Sevele interrupted regular programs on state radio and television late Tuesday to make an announcement about the 88-year-old king's failing health. Details of his health problems were not released, though he has struggled with obesity for years.

King Tupou IV, who has ruled Tonga for 41 years, has been in Auckland for medical treatment since early April, briefly returning to Tonga for celebrations for his 88th birthday on July 4.

Tupou IV has been the absolute ruler of the chain of more than 170 islets in Polynesia since 1965.