Emergency response was “calm and collected†after a bomb blast in central Bangkok killed at least 18 people on Monday, according to a Canadian witness who was at the scene minutes after the explosion.

“Everything seemed to be working in a co-ordinated fashion,†said Derek Van Pelt, a Bangkok resident and vice-president of the Thai-Canadian Chamber of Commerce. “I’m really impressed with the resilience of the Thai people.â€

The explosion occurred during rush hour at the Erawan Shrine, an important religious landmark and popular tourist destination located near many five-star hotels and upscale shopping malls in the city’s centre.

The area around the shrine was filled with hundreds of tourists, shoppers and workers at the time of the blast. Officials say the bomb -- made from a pipe wrapped in cloth -- killed at least 18 people and injured 117.

Security camera footage showed powerful flash as the bomb went off at around 7 p.m. local time Monday.

Van Pelt said the extent of the damage caused by the blast was immediately clear when he arrived at the scene.

“It was clearly a very large explosion,†said Van Pelt, who has been living in Bangkok for 17 years. “Windows were shattered, there were definitely injured people around and several bodies were still on the scene.â€

No one has claimed responsibility for the blast, which caused the worst damage of any single attack in the city’s recent history. The explosion was one of the few violent incidents to hit the country since a military coup that ousted Thailand’s civilian government in May 2014.

The Erawan shrine is dedicated to the Hindu god Brahma, but the monument is also extremely popular among Thai and Chinese Buddhists.

With files from the Associated Press