Bangkok: Thai police have found a motorcycle allegedly left on the street by the Iranians detained in connection with recent blasts, with investigators probing whether there was a plan to use the bike for the attack.

An owner of an electrical appliances repair shop alerted police after he noticed the Honda Wave that had been parked in front of his shop for a long time.

Bomb disposal experts and forensic police rushed to the scene and checked the motorcycle, which was purchased from a shop in the Klong Tan area by one of the suspects, said Thailand's deputy police chief Pol Gen Pansiri Prapawat.

A police source said the motorcycle was bought for 26,400 baht (USD 844) by Masoud Sedaghatzadeh, 31, who was arrested in Kuala Lumpur on Wednesday after fleeing Thailand.

The Bangkok Post newspaper said that police found a sticker with the word "SEJEAL" under the motorcycle's seat.

Palestinian militants have referred to their rockets and mortars used to attack Israel as "sejeal stones."

Local media quoted witnesses as saying that suspects used the motorcycle for travelling but police are investigating if they planned to use it for a bomb attack.

Two Iranians are currently in custody in Bangkok.

Saeid Moradi, 28, was injured in one blast and is being treated at Chulalongkorn Hospital, while Mohammad Khazaei, 42, was detained at Suvarnabhumi airport.

The third suspect is Sedaghatzadeh, while the fourth suspect is female, Leila Rohani, who has fled to Iran.

A court has approved a police request to issue a warrant for the fifth suspect who was seen on surveillance camera footage near a house just before an explosion ripped through it on Tuesday.

Rohani entered Thailand four times last year. She flew back on February 5.