HONOLULU (KHON) — Early morning travelers at Hilo International Airport on Hawai’i Island had a rough start to their travel day Tuesday.

At around 5:45 a.m., Transportation Security Administration agents say they found two grenades while conducting routine screenings of travelers’ carry-on property.

Initially, agents noticed a suspicious item as a bag traveled through the X-ray machine.

The area was evacuated immediately following the discovery to protect airport employees and departing travelers until explosive specialists arrived.

Authorities said the grenades were in a carry-on bag belonging to 41-year-old Akito Fukushima of Japan, who was returning home.

Upon further examination, the grenades were determined to be inactive and had been rendered powerless. It’s not clear where the grenades came from or what the man intended to do with them.

“He cooperated with officials, however, it is undetermined at this time as detectives are continuing their investigation,” said Hawaii Police Capt. Brian Prudencio.

Fukushima was arrested on charges of first-degree terroristic threatening, which is a class C felony.

Airport operations resumed around 6:50 a.m.

“TSA reminds everyone that grenades of any type — including replicas — are not allowed in either checked or carry-on luggage,” TSA spokesperson Lorie Dankers said. “When a traveler brings any type of grenade to the airport, it causes operations to shut down and delays travelers. Please, be aware of the contents of your luggage prior to coming to the airport to avoid this type of situation from occurring.”

Hawaii police said the suspect in Tuesday morning’s arrest is in custody and awaiting charges.