Police believe that one of the men is known as — "Dragon" — and is based in Samut Prakan. They also believe he is connected to a former politician.
They two were said to have arrived by taxi at Siam Paragon and were quiet and composed.
Pol Gen Chakthip Chaichinda, deputy national police chief, said the bomb-maker was likely a professional and there were likely many others in support of the operation.
Police probe Min Buri blast links
Police said Tuesday (February 3) investigators believe the two explosions near Siam Paragon on Sunday are linked to a deadly blast which killed two men in Min Buri during the Bangkok Shutdown protests, almost a year ago.
Metropolitan Police chief Sriwara Rangsiphramanakul said that investigators had examined bomb fragments collected from the blast and found that 90% of them were similar to those found at the Min Buri blast scene.
Speaking after a meeting with investigators handling the bomb incident, Pol Lt Gen Sriwara said photos of two suspects captured on security camera footage at Siam had been compared to those suspected of involvement in a spate of bombings during anti-government protests last year.
On March 29 last year, two men were killed when a home-made bomb hidden in a motorcycle they were riding accidentally exploded in a car park in Min Buri.
Police later searched their house nearby and found bomb-making equipment.
The deceased were probably members of a group using the house to assemble explosives, said police.
According to police, the two men were members of a group of 10 who rented a house for assembling home-made bombs destined for use in attacks in public areas.
The attacks occurred at the height of anti-government demonstrations led by the People's Democratic Reform Committee (PDRC).
Sunday's explosions occurred on a walkway between Siam BTS station and Siam Paragon shopping centre at 8.20pm, sparking panic among shoppers and tourists.
Two people were slightly injured.
Police spokesman Prawuth Thawornsiri said police were seeking arrest warrants for two men captured on CCTV loitering near Siam Paragon shortly before the blasts.
The footage shows two Asian men of moderate height, one wearing a white cap, and the other wearing a black cap, with suspicious-looking bags, Pol Lt Gen Prawuth said.
Security has been stepped up at places where crowds gather, including BTS stations, bus terminals, department stores, cinemas and night markets.
Also on Tuesday, army chief Udomdej Sitabutr said his intelligence units are sharing information with police handling the investigation.
Police are leading the probe, with the military working as their assistants, he added.
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