Suspect Hunted as Second Blast Rocks Bangkok

The second explosion occurred at a ferry pier with police reporting no injuries, Sky News reported on Tuesday.

Police Senior Sergeant Major Worapong Boonthawee says an explosive device was thrown from the Taksin Bridge on Tuesday afternoon and blew up at Sathorn Pier after falling into the Chao Phraya River below.

Security camera footage showed a sudden blast of water dousing people on a walkway at the pier, as bystanders ran for safety.

Meanwhile Thailand's junta leader says a suspect has been identified in the bombing at a Bangkok religious shrine that killed at least 20 people.

The attack occurred on Monday in one of the Thai capital's most popular tourism hubs, ripping through a crowd of worshippers at the Hindu shrine close to five-star hotels and upscale shopping malls.

Chinese, Hong Kong, Singaporean, Indonesian and Malaysian citizens were among the 20 people killed, police said.

More than 100 other people were injured as the blast left body parts strewn across crushed pavement, alongside shattered windows and incinerated motorcycles.

Prime Minister Prayut Chan-ocha on Tuesday gave the first indications who authorities believed was responsible, condemning the bombing as the 'worst ever attack' on the kingdom.

'Today there is a suspect ... we are looking for this guy,' Prayut said, adding the man was seen on closed circuit television at the blast site.

Prayut said the male suspect was believed to be from an 'anti-government group based in Thailand's northeast', the heartland of the kingdom's Red Shirt movement that opposes the military junta.

Bangkok has endured more than a decade of deadly political violence, with the junta ruling the nation since May last year after toppling the elected government of Yingluck Shinawatra.

The Red Shirts are a grassroots network of rural and urban poor that are loyal to Yingluck and her self-exiled brother, Thaksin Shinawatra, who was a previous prime minister.

But no one claimed responsibility for the assault and security analysts expressed scepticism over the government's lightning move to cast suspicion on its opponents.

Junta leaders said the bomb was aimed at damaging the country's tourist industry, which is a rare bright spot in an otherwise gloomy economy, and tarnishing the junta's reputation.

'(The attackers) had the clear target of destroying our economy and tourism .... and discrediting the government,' Defence Minister Prawit Wongsuwon told reporters.

Thailand's baht currency slumped to a more than six-year low on Tuesday and shares fell in Bangkok over concerns the attack could damage the tourism sector.

Police have tightened security across Bangkok, with hundreds of schools closed and checkpoints thrown up across the city.

The bomb was detonated shortly before 7.00pm local time in the middle of the city's rush hour, sending a fireball into the sky as commuters and tourists fled in panic.