While the source of the explosion is not confirmed many people suspect a bomb blast. The image of a crater inside the Erawan shrine seems to point to a bomb blast.
BBC journalist, Jonathan Head, also reported seeing body parts strewn about.
In the last few minutes deputy national police chief Aek Angsananond said: "All I can say now is there has been an explosion in central Bangkok involving a motorcycle bomb."
The blast happened around 7p.m. Thai time.
Emergency teams of first responders are at the scene. The death toll at this time is 12 with around 70 people reported injured; both are expected to rise.
Police are overseeing an evacuation of the area and fear another bomb.
Reports at time of writing are sketchy; updates will follow as details become available.
Latest update Monday:
Within a few short hours the death toll is revised up. It now is reported by some to stand at 16. Three of the dead were foreign tourists; two from China and one from the Philippines.
Around 80 people sustained injuries.
Earlier reports of 4 foreign tourists dead and a death toll of 27 have been revised down.
Marko Cunningham, a New Zealand paramedic working with a Bangkok ambulance service told Reuters the blast had left a two-meter-wide (6-foot-) crater and he likened the bloody scene to a" meat market."
"There were bodies everywhere. Some were shredded. There were legs where heads were supposed to be. It was horrific."
The tragedy could have been much worse; there are reports of two other explosive devices.
Officials in Thailand say they are fighting an ongoing low-level Muslim threat in the predominantly Buddhist southern part of the country. Those rebels however tend to stick to that southern area of Thailand.
As yet no terror or rebel organisation has claimed responsibility for the attack.
It is widely accepted that the motive for the attack was to undermine the Thai economy and strike against the lucrative tourist trade.
Perhaps if a group or individual claims responsibility that view may change.