The attacks came on a busy weekend for tourism as domestic and international visitors flocked to seaside resorts on a long weekend
A series of bombing and arson attacks in southern Thailand that killed four people and wounded dozens was "clearly connected", Deputy Police Chief Pongsapat Pongcharoen said on Sunday, and an arrest warrant had been issued for a man in relation to one of the arson attacks.
The bombs on Thursday and Friday went off in the upscale resort of Hua Hin, and beach destinations in the south including Phuket, Phang Nga and Surat Thani, a gateway city to popular tourists islands in the Gulf of Thailand.
Police and Thailand's foreign ministry initially ruled out links to Islamist terrorism and foreign terror groups, though national police chief Jakthip Chaijinda later told reporters on Friday that the devices were similar to those used by Muslim separatists.
The attacks came on a busy weekend for tourism as domestic and international visitors flocked to seaside resorts on a long weekend for a public holiday.
Pongsapat said that the Region 3 police commander overseeing Hua Hin area has offered a cash reward for anyone who has information that can help authorities find a suspect.
Hua Hin, an easy weekend getaway for residents of Bangkok, was returning to normal on Saturday - though most businesses in the vicinity of the Thursday night explosions remained closed, a Reuters witness said.
"These acts were undertaken by a group in many areas simultaneously, following orders from one individual," the deputy national police chief told reporters on Sunday.
The arrest warrant was issued in relation to an arson attack on a supermarket in Nakhon Si Thammarat early on Thursday, Pongsapat said.