Damage is visible on the statue of the Hindu god Brahma, following Monday's bombing at the Erawan Shrine at Rajprasong intersection in Bangkok, Thailand. The shrine reopened Wednesday to the public. Photo: AP

Police photofit of one of the bombing suspects. Photo: AFP

Thai authorities said Wednesday the man who carried out a devastating Bangkok shrine bombing that killed 20 people was a foreigner and part of a network.

The attack occurred on Monday as worshippers crowded into the Hindu shrine in the Thai capital, shredding bodies and incinerating motorcycles.

Seven Chinese tourists were killed, China Central Television reported.

Police on Wednesday released a sketch of a young man shown on security footage walking into the shrine and placing a backpack believed to contain the bomb, which detonated a few minutes later.

A few hours after the sketch was released a Bangkok court issued an arrest warrant for the man depicted, describing him as a tall foreigner with white skin.

The warrant accused the "unnamed foreigner of premeditated murder, attempted murder and bomb-making."

Police spokesman Prawut Thavornsiri earlier tweeted that police were offering a 1 million baht ($28,100) reward for information leading to the arrest of the suspect.

Before the arrest warrant was made public, national police chief General Somyot Poompanmoung told reporters a "network" had orchestrated the attack.

Prawut said his features were gleaned partly from security footage taken of him at the shrine in the minutes before the attack.

He said the profile had also used information gathered from interviews with the drivers of the motorcycle taxis that the suspect used to arrive at the shrine and leave it.

Prawut said two other men seen in the footage near the scene are also suspects, bringing the number of suspects police have said they are actively looking for to three.

"The person in red and the person in white are also suspects," he said.

At least two foreigners have been interviewed in connection with the blast, police said.

The government says the attack was aimed at wrecking the economy, which depends heavily on tourism.

No one has claimed responsibility for the blast. 

Jangling nerves in the city on Tuesday, a small explosive was thrown from a bridge towards a river pier, sending a plume of water into the air, but no one was hurt.

A government spokesman initially said there were "patterns" linking the two bombs which both used TNT, but police chief Somyot said no direct connection between them had been established.

Police Major General Pornchai Suteerakune, commander of the Institute of Forensic Medicine, said the bodies of almost all those killed at the shrine had wounds inflicted by ball bearings that were packed into the bomb.

The shrine, a blood-spattered scene of charred motorbikes and debris after the blast, was reopened on Wednesday.