An unidentified flying object crashed on Phu Quoc island Tuesday.

From the debris, authorities suspect it to be an airplane but in the absence of markings on them or the remains of passengers, no firm conclusions have been made.

Residents in the north of the island said they heard explosions in the sky at around 11 am and then saw a black object plunge to ground, leaving a white trail of smoke behind.

Island authorities confirmed they found six pieces of metal, some with screws on them, with the biggest being about 1.5 meters long.

Truong Quoc Tuan, the Kien Giang Province Party Committee chief, said the explosion occurred in airspace used for international flights.

But no sign of persons piloting the object has been found.

Officials had informed airlines in Vietnam and nearby countries, but no plane crash report had been reported until Tuesday night, Tuan said.

The island's militia has started searching for possible human victims and for more debris to identify the object and find out the cause of the explosion.

Luckily for local residents, the debris fell in a thinly populated area.