Philippine military officials say the country's navy chief has been relieved from his post reportedly due to differences with other security officials over a frigate deal.

Military spokesman Col. Edgard Arevalo said Tuesday that the military chief of staff, Gen. Rey Leonardo Guerrero, has enforced orders from "higher authorities" and assigned Vice Adm. Ronald Joseph Mercado to his office and installed an acting navy chief, Rear Adm. Robert Empedrad.

Arevalo said "the reason for this change-of-command will be explained in due time."

In a letter seen by The Associated Press, however, Defense Secretary Delfin Lorenzana complained that Mercado, through his subordinates, "had continued to trifle" with the Department of Defense's decision in connection with a frigate deal, which the department awarded to Hyundai Heavy Industries of South Korea last year.