Cambodia's King Norodom Sihanouk has abdicated, according to the head of the National Assembly Thursday in Phnom Penh.

The king made the announcement in a letter read to the National Assembly early Thursday by his son Prince Norodm Ranariddh, who is also head of the assembly.

"I ask all compatriots to please allow me to retire," the king's letter said. The king also asked the people to begin a search of a successor, said Ranariddh.

The king asked the country to form a nine-member throne council to consider the next monarch, the statement said.

The king said in statement that he asked retirement because of his fragile health.