A call made Friday to Nagoya airport in which a man claimed that a Northwest Airlines plane traveling from Detroit to Manila via Nagoya was going to be hijacked was a false alarm, according to the transport ministry.

The ministry said the caller had spoken in Japanese, saying, "Something bad will happen aboard today's Northwest Airlines flight bound for Manila . . . this is not a bluff."

During the call, which was made at around 12:25 p.m. and lasted about 30 seconds, the man said two women and three men were going to hijack the plane and that the women were linked to the Taliban regime in Afghanistan. Police refused to confirm an earlier report claiming that the person who made the call had been detained and said they are looking for the culprit.

Investigative authorities said the plane had issued no hijack alarms or signals, while the Land, Infrastructure and Transport Ministry said operations aboard the aircraft were continuing as usual.