Malaysia's prime minister has urged Philippine authorities to punish kidnappers who reportedly beheaded a Malaysian man in the southern Philippines, saying he and his people are "shocked and sickened" by the savage act.

The Philippine military said it is verifying intelligence reports that the militants killed Bernard Then Ted Fen in a jungle in Sulu province, where the militants are holding other captives.

Prime Minister Najib Razak called on authorities late Tuesday to take action against those behind "this savage and barbaric act."

Then was abducted with a compatriot, Thien Nyuk Fun, by Abu Sayyaf gunmen in May in the Malaysian state of Sabah and taken by boat to Sulu. Thien was freed earlier this month after a ransom was reportedly paid.