TEHRAN, Iran (AP) – An Iranian airliner was forced to return to a southern airport minutes after takeoff when a homemade bomb was found aboard, said state television, in an incident a security official called a “sabotage operation.”

The report said the bomb was found in a toilet, but gave no other details on the device. The incident took place late Saturday night.

As Iran prepares for its June 12 presidential election, there have been a number of violent incidents. A bombing Thursday at a mosque in another southern city of Zahedan killed 25 people and wounded 80. A day later, a shooting at President Mahmoud Ahmadinejad’s campaign office in the same city injured three people.

Air guards chief Mohammad Hasan Kazemi, speaking to the official IRNA news agency, left open the possibility of a link between those two incidents and the package on the airliner. He said “enemies” were trying to create a sense of hopelessness among Iranians before the election.

The plane, carrying 140 passengers, returned to an airport in the southwestern city of Ahvaz 15 minutes after takeoff Saturday after a passenger reported a suspicious package. The plane belongs to one of Iran’s commercial airlines, Kish Air.

The flight was from Ahvaz to the capital, Tehran, about 500 miles (800 kilometers) to the northeast.