MANILA — The remains of the Philippine dictator Ferdinand E. Marcos were buried Friday at the national cemetery. A brief announcement a few hours beforehand stunned activists and Marcos opponents who said he did not deserve the honor.

The service, which was closed to the public, began around noon at the cemetery, the Philippines’ equivalent of Arlington National Cemetery. Journalists posted photos on social media of police with riot shields barricading the entrance to the cemetery in Taguig City, part of greater Manila.

The reburial of Mr. Marcos, which his family had sought for decades, was approved by the Supreme Court on Nov. 8. But while the family had said it would proceed with the funeral plans, the announcement on Friday, coming shortly before the service was to start, was unexpected. Opponents of the decision had planned a demonstration that day.

Mr. Marcos was ousted in a popular uprising in 1986 and died in the United States three years later. His body was brought back to the Philippines in 1993 and has been stored in a crypt in his hometown, Batac.