“Please be careful,” said a passenger to a flight attendant who was helping her to put her bag in the overhead locker. “I’m carrying a bomb there,” she said.

The passenger, identified as Henny Adiaksi, and her belongings were taken from the plane. A security check was performed, and an X-ray examination found no explosives, as reported by detik.com. She later admitted that it was only a joke.

The incident happened on June 2 on a Garuda Indonesia airplane heading to Singapore from Jakarta. It was not an isolated case.

In May alone, there were 10 airplane “bomb jokes” across Indonesia. The term itself has been rejected by the Indonesian Ombudsman. The situation could not be more serious following a string of terrorist incidents in May that rocked Indonesia, starting with the riot in a detention center in the National Police’s Mobile Brigade headquarters in Depok, West Java, on May 8, suicide bombings by families in East Java on May 13 and May 14 and another such attack against the Riau Police headquarters on May 16.

“As long as we use the term ‘joke’, we will continue to treat it as such,” Ombudsman member Alvin Lie told kompas.com on Friday. The institution has advised treating “bomb jokes” as actual terrorist threats.

As stipulated in Article 437 of Law No. 1/2009 on national flight safety, anyone who makes a false statement that could endanger flight safety faces up to one year in prison. If the false statement causes losses or an accident, the violator could face up to eight years in prison. If the false statement causes a fatality, the violator could face up to 15 years in prison.

The following are 10 cases that were reported in May:

May 2: A passenger, identified only as FW, on a Lion Air aircraft due to take off from Jakarta bound for Belitung, warned there was a bomb on the aircraft. All passengers were ordered to leave the plane by the crew and the plane was searched. The flight was delayed for two hours, according to kompas.com.

May 5: Another Lion Air passenger, identified only as ST, said that there was a bomb inside her bag as a flight attendant helped her put her bag in the overhead locker, as reported by Antara. The plane was at Sultan Hasanuddin International Airport, Makassar in South Sulawesi, heading to Juanda International Airport, Surabaya, East Java. ST was questioned by security staff of the Makassar office of airport operator PT Angkasa Pura I.

May 12: A Lion Air passenger in Jakarta, identified only as ZN, reportedly uttered the word “bomb” to a flight attendant upon boarding flight JT 618 flight bound for Pangkalpinang, Bangka, as quoted by kompas.com. The flight was delayed, while all 148 passengers with their luggage had to be rechecked for security reasons. Lion Air offloaded ZN and four persons traveling with him, including 10 pieces of luggage, from the plane. ZN then faced multiple investigations by the airline’s security staff, airport security and the police.

May 16: A Lion Air passenger, identified only as DB, claimed to be a terrorist carrying a bomb in his bag while boarding a plane ready for takeoff at Sultan Syarif Kasim II International Airport, Pekanbaru, Riau, heading to Jakarta’s Soekarno-Hatta International Airport. The flight was delayed for more than two hours for security examination. DB was detained by security staff, according to kompas.com.

On the same day, two separate Batik Air flights faced bomb threats, according to kompas.com. On flight ID 6659, a passenger, identified only as ET, was forced to leave the plane after claiming to be to carrying a bomb. A ground-handling officer at Lombok International Airport repeatedly asked ET about his luggage, the shape of which appeared suspicious.

On flight ID 6140 from Jakarta to Ternate, a passenger identified only as RA, was forced to leave the plane after muttering the word “bomb” in front of a flight attendant while boarding. An examination of the passengers and cargo found no explosives.

May 18: A Lion Air passenger, identified only as EF, told cabin crew on flight JT 261 that he had brought a bomb onto the aircraft. EF was removed from the plane and questioned by airport security officials.

May 23: Two Garuda Indonesia passengers were questioned by security officers at Banyuwangi Airport in East Java for joking that one of them was carrying a bomb inside his bag. The two were revealed to be members of Banyuwangi Legislative Council (DPRD), Basuki Rachmad from Hanura and Nauval Badri from Gerindra. Nauval had insisted that a lighter and perfume were explosives, as reported by kompas.com.

May 27: Lion Air removed a passenger, identified only as YS, from a flight departing from Soekarno-Hatta International Airport bound for Kuala Lumpur International Airport after the passenger joked about the presence of a bomb on board. YS was later taken into police custody. The flight was scheduled to depart from Soekarno-Hatta at 11:40 a.m. but was forced to delay its departure until 2:15. p.m.

May 28: Lion Air removed a passenger, identified only as FS, from a flight that was due to depart from Supadio International Airport, Pontianak, West Kalimantan, bound for Soekarno-Hatta International Airport. FS allegedly said there was a bomb in his luggage because he was angry that one of the attendants had treated the luggage roughly. Passengers opened an emergency door in panic and jumped from the plane’s wing, at least 10 people were injured in the incident.