Police in Thailand led two suspects to the scene of last month's Bangkok bomb blast for a re-enactment of their alleged crimes on Saturday, a day after police said one of the men was responsible for planting the bomb that killed 20 people.

Fourteen foreigners were among those killed in the attack, the worst incident of its kind in Thai history. It dealt a fresh blow to Thailand's important tourism industry, which had just begun to recover after political protests last year.

Police escorted the two men to the shrine and a nearby shopping mall in the Thai capital.

The men, handcuffed and wearing body armour, walked through the re-enactment, a standard Thai police procedure, while bystanders were kept at a distance.

National police spokesman Prawut Thawornsiri said on Friday one of the two men was the same yellow-shirted man seen in security footage placing a backpack at the shrine moments before the blast.

Prawut told reporters at the shrine on Saturday that the first arrested suspect, who has been referred to both as Bilal Mohammed and Adem Karadag, the name on a Turkish passport he holds, was responsible for the bombing.

"We have now identified him as the one who killed 20 people and injured many others," said Prawut.

Karadag, whose nationality remains unconfirmed, wore a yellow shirt on top of his prison uniform and sat on a bench at the shrine during the re-enactment - the same place the man seen in security footage left the backpack containing the bomb.

The second man arrested, Yusufu Mieraili, used a mobile phone to trigger the bomb, Prawut said without giving further details.

Mieraili, dressed in a dark blue shirt, went through his re-enactment near a shopping mall a stone's throw from the shrine, from where police say he detonated the bomb.

Authorities had earlier said it was unlikely that either of the two men detained over the Aug. 17 blast were the bomber in what has been an often contradictory police investigation.

Police had also said they believed Mieraili conspired in the attack but did not detonate the bomb.

Karadag's lawyer, who says his client's real name is Bilal Mohammed, said Karadag maintains he is innocent and had last visited him on Sept. 15.

"The appearance of the yellow shirt man [in CCTV footage] and Adem do not match. I do not believe Adem would confess," lawyer Chuchart Kanphai said.

The motive for the attack remains unclear.