TOKYO — A helicopter carrying two sightseers has gone missing near Mount Aso, one of Japan's most active volcanoes.

The aircraft took off from a zoo in Aso City at 10:52 local time (01:52 GMT) on Tuesday for a 10-minute tour but never returned, BBC reported, citing local media.

An object resembling an aircraft was spotted by a police helicopter inside the crater of Nakadake, one of Mount Aso's five peaks, at around 16:00. Authorities have yet to confirm if it is the missing helicopter.

The helicopter's 64-year-old pilot was a veteran with 40 years of experience, according to local media. His passengers were a man and a woman, both Taiwanese.

The aircraft, a US-made Robinson R44, was on its third sightseeing trip for the day when it went missing. There was no issue with its two earlier journeys, according to the helicopter's operator Takumi Enterprise.

Cloudy weather was reported over the Nakadake area on Tuesday and search operations were suspended Tuesday evening, before resuming Wednesday morning.

Takumi Enterprise grounded all of its helicopters following the incident, according to Jiji news agency.

Helicopter tours over the volcanic landscapes of Mount Aso are among the major tourist draws of Kumamoto prefecture, in south-west Japan.

In 2024, a Takumi Enterprise sightseeing helicopter flying over Mount Aso made an emergency landing, injuring the three people on board.

Mount Aso last erupted in October 2021, sending a massive plume of smoke into the sky. — Agencies