Update as of 6:26 a.m. EDT: A man in a yellow T-shirt seen in surveillance footage leaving the Erawan Shrine Monday night is “the bomber” responsible for the explosion at the popular shrine in Bangkok that killed at least 21 people, Police Lt. Gen. Prawut Thavornsiri, told the Associated Press.

Update as of 6:06 a.m. EDT: A Thai official identified a man wearing a yellow T-shirt and carrying a backpack as a suspect in Monday's bombing at a popular shrine in downtown Bangkok that killed at least 21 people, according to the Associated Press.

Earlier, photos of the suspect were released by Police Lt. Gen. Prawut Thavornsiri on social media. Authorities reportedly said that the images were taken from a closed-circuit camera at the Erawan Shrine before the explosion.

In surveillance footage released by authorities, BBC reported, the suspect is seen removing his backpack in the crowded shrine and then immediately leaving the scene without it.

Update as of 4:30 a.m. EDT: Thai police confirmed Tuesday reports of a second explosion in Bangkok, a day after a bombing at a shrine killed at least 21 people. Authorities said there were no injuries reported from the latest incident.

An unidentified man threw a small explosive from a bridge in central Bangkok, Col. Natakit Siriwongtawan, deputy police chief of Klongsan district, reportedly said."If it did not fall in the water then it certainly would have caused injuries," he said.

Original story:

Authorities are looking for a “suspect” seen on surveillance footage near the scene of a bombing in Bangkok Monday night that killed at least 21 people and injured more than hundred, Thailand’s Prime Minister Prayuth Chan-ocha said Tuesday. President Tony Tan condemned the “terrible act of terror” and promised to work on finding the perpetrators swiftly.

The explosion occurred Monday near a popular shrine in the crowded downtown area of Thailand's capital. Authorities reportedly said that at least 10 people from Thailand, three Chinese, two Malaysians, and one Filipino national were among the dead. A 31-year-old Japanese man is among the seriously injured in the bombing, the Associated Press (AP) reported, citing Japanese media. Prayuth on Tuesday vowed to trace down those responsible for the bombing as investigators probed the scene for clues into the incident.

“Today there is a suspect who appeared on CCTV but it's not clear... we are looking for this guy," Prayuth reportedly said, adding that the suspect was believed to be from an "anti-government group based in Thailand's northeast.

"This is the worst incident that has ever happened in Thailand," Prayuth said, according to AP. "There have been minor bombs or just noise, but this time they aim for innocent lives. They want to destroy our economy, our tourism."

Defense Minister Prawit Wongsuwan reportedly said that Thai authorities had no intelligence on the attack before the blast. No one has so far taken responsibility for the bombing, which occurred in a part of the city crowded with locals and tourists alike.

The Hong Kong Travel Industry Council Tuesday urged the government to raise the travel alert to 'black' -- its highest security warning -- for Thailand in the wake of the deadly bombing.

National chief of police Somyot Poompanmoung reportedly said the perpetrators aimed to kill "because everyone knows that at 7 p.m. the shrine is crowded with Thais and foreigners. Planting a bomb there means they want to see a lot of dead people."

He added that the bomb, which appeared to have been attached to a small motorbike outside the shrine, was made with a pipe wrapped in cloth and weighed over six pounds. The area, which is normally a busy intersection, remained cordoned off early Tuesday as police tightened security, media reports said. 

“It is much clearer who the bombers are, but I can't reveal more right now," Prawit reportedly said Tuesday. "We haven't ruled out terrorism."