Broken glass from the blast is pictured near the site of a deadly blast in central Bangkok, Thailand, August 18, 2015. [Photo/Agencies]

The improvised explosive device scattered body parts, spattered blood, blasted windows and burned motorbikes to the metal. The explosion went off around 7 pm in an upscale area filled with tourists, office workers and shoppers. No one has claimed responsibility.

Bangkok was rocked again Tuesday when another explosive device blew up at a ferry pier, but no one was hurt.

Police Senior Sgt. Maj. Worapong Boonthawee said an explosive device was thrown from the Taksin Bridge and blew up at Sathorn Pier after falling into the Chao Phraya River below. "There is no injury," he said. Security camera footage shows a sudden blast of water over a walkway at the pier as bystanders run for safety.

Prayuth gave his first televised address since the bombing Tuesday, saying the government will expedite "all investigative efforts to find the perpetrators and bring them to justice."

Defense Minister Prawit Wongsuwan said authorities had no idea an attack had been planned.

"We didn't know about this ahead of time. We had no intelligence on this attack," the defense minister said.

Prayuth vowed to "hurry and find the bombers," though he noted there may be just one perpetrator. Speaking to reporters, he continued what has been a notoriously prickly relationship with the media since the former general took control of the government in a May 2014 coup.

Asked if there were leads on the suspects' identities, Prayuth bristled, "We are still investigating. The bomb has just exploded _ why are you asking now? Do you understand the word investigation? It's not like they claim responsibility."

Experts investigate the remains of destroyed motorcycles at the Erawan shrine, the site of the blast in central Bangkok August 17, 2015. [Photo/Agencies]