`This bomb has many characteristics similar to a type of low-destructive explosive device, which can be made from black powder or homemade explosives,` said Patrick Senft, an expert at the Armament Research Agency.

The bomb was thrown by suspect Ryuji Kimura, 24, at Prime Minister Fumio Kishida when he came to give a speech at the Saikazaki fishing port, Wakayama city in the province of the same name on April 15.

The object exploded while the Japanese prime minister spoke

Security forces control the bombing suspect at the place where Prime Minister Fumio Kishida spoke on April 15.

The object fell about a meter away from Mr. Kishida.

Because the object created a lot of smoke after the explosion, Japanese media identified this as a homemade smoke bomb.

The bomb, about 20-30cm long, is made of metal pipe, with wires at both ends covered with screw caps.

Photos of the scene showed that the bomb emitted a lot of smoke before exploding, proving that it used a slow-burning wire, experts said.

The bomb was thrown towards Prime Minister Kishida on April 15.

On April 16, Japanese police searched the suspect’s house in Hyogo province and discovered powder suspected to be black explosives, metal pipes and many bomb-making tools.

Matthew Moss, a weapons expert in the UK, said pipe bombs are relatively easy to make and are one of the simplest types of improvised explosive devices.

According to Moss, if made properly, this type of pipe bomb can create fragments strong enough to cause fatal injuries.

Regarding the limited destructive power of the pipe bomb in the attack, experts explained that the cause may have been due to the quality of the explosives and the suspect’s errors in the assembly process.

`The bomb seemed to be defective. Even though it caused a loud explosion, the bomb did not have enough pressure to create fragments from the tube casing,` said expert Senft.

Moss also raised the possibility that the bomb malfunctioned, when part of the screw cap came off, preventing it from creating enough pressure to cause shrapnel to fly.

Police carry evidence confiscated after the search of suspect Ryuji Kimura’s house on April 16.

The chaotic scene in this attack is reminiscent of the assassination of former prime minister Shinzo Abe 9 months ago.

The two attacks raised questions about measures to prevent the production and use of homemade weapons in Japan.

`Legal regulations can hardly stop individuals who want to build such a simple explosive device,` said expert Senft.