A US serviceman and three employees of a subcontractor hired by the US military died in a plane crash in the Philippines, world agencies reported.
The US military's Indo-Pacific Command said the plane it hired was carrying out a routine mission "with support for intelligence, surveillance and reconnaissance at the request of its Philippine allies," the Associated Press reported. It said the cause of the crash was under investigation.
The Civil Aviation Authority of the Philippines confirmed the crash of a small plane in Maguindanao province.
The bodies of the four dead were found in the wreckage of the plane in Ampatuan city, said provincial security official Amer Jehad Tim Amboloto.
The Indo-Pacific Command said the names of the crew members would not be released until their families were notified.
There were no reports of injuries to residents in the area of the crash, the AP noted.
A water buffalo was killed in the crash, local authorities said.
For a decade, American troops have been stationed at Philippine bases in the south of the country, helping advise and train government forces in their fight against Islamist militants.
In The area has a Muslim minority. The Catholic Christian faith is predominant in the Philippines.