The ministry didn't name the vessel, but Russian media reported it was the country's most secret submersible, a nuclear-powered research submarine called the Losharik intended for sensitive missions at great depths.
President Rodrigo Duterte has ordered government forces to destroy the Abu Sayyaf terrorist network after the bombing last Sunday of Our Lady of Mount Carmel Cathedral in the Sulu provincial capital of Jolo that killed 22 people and wounded more than 100.