Militants in the Philippines have released a video showing the beheading of a German hostage.
Jurgen Kantner was abducted from his yacht off Malaysia in November.
A deadline set by the militants for a ransom payment equivalent to about $600,000 expired on February 26.
The brief video released by the Abu Sayyaf militant group on February 27 was circulated by the SITE Intelligence Group, which monitors extremist websites.
The footage shows the 70-year-old Kantner being beheaded by a group of masked men using a curved knife.
Presidential adviser Jesus Dureza confirmed Kantner's death and condemned what he called a "barbaric" execution.
Dureza said authorities had tried their best to locate and free Kantner but "to no avail."
German Foreign Ministry spokesman Martin Schaefer said experts were evaluating the authenticity of the video.
Schaefer said if the footage is authentic, it is "deeply shocking."
Abu Sayyaf is considered a terrorist organization by the United States and the Philippines.