At least one person was killed and 20 others were injured on Thursday in a twin bomb attack in the popular Thailand resort of Hua Hin.
Foreign tourists were among those hurt by the bombs, which were hidden in two plant pots, police said.
At least four people were said to be in a critical condition last night, and it was unclear whether any British nationals were injured in the attack.
Police said the explosives were detonated remotely via mobile phone and had been placed roughly 160ft apart. The bombs went off within half an hour of each other, according to the BBC.
Sitthichai Srisopacharoenrat said the victim who died was a Thai women. Initial reports on social media said she was a market vendor.
One eyewitness said a man and his child were badly injured in the attack and had “bones sticking out of their legs.”
Another, a British man named Mark Gainsford, told the BBC: “I heard people shouting ‘Bomb! Bomb!’ but I didn’t hear any blast.”
“I ran out to see if I could help. I saw eight to 10 people injured, on the floor. The police arrived very quickly.”
A Foreign Office spokesman said: “We are seeking further information following an incident in Hua Hin, Thailand.
“We stand ready to provide assistance to any British nationals involved.”
Separatist rebels frequently carry out attacks in Thailand’s southern provinces, but bombings in the country’s tourist areas are rare.
Hua Hin is a coastal resort on the Gulf of Thailand and is popular with locals as well as foreign tourists. In April 2016, the resort made headlines after an elderly British couple were knocked unconscious by local thugs.
CCTV footage showed a brief argument before the attackers kicked and punched Rosemary Owen, 65, and her husband, Lewis, 68.
Mrs Owen suffered a serious head injury and had to be rushed to hospital, where doctors drained a build-up of fluid from around her skull. Her husband needed several stitches to his head. Her son, John Owen, 43, was also injured in the attack, which took place during Thai New Year celebrations.
Four Thai men confessed to the vicious assault and were jailed for two years after issuing an apology to the family.