A wave of co-ordinated explosions have hit cities in Thailand, killing several people and wounding dozens more.
Among the injured were 10 foreigners in the seaside resort town of Hua Hin.
It was not clear who was behind the attacks, but the timing and scope suggested they were carried out by opponents of the ruling junta, which last weekend organised a successful referendum on a constitution that critics say will bolster the military's power for years to come.
The violence took place on the birthday of Thailand's Queen Sirikit. The junta has repeatedly said that defending the monarchy is a top priority and the army and its allies are keen to ensure a smooth succession for ailing 88-year-old King Bhumibol Adulyadej, the world's longest reigning monarch.
The first two explosions occurred overnight on a busy street in the tourist area of Hua Hin, which was hit by a further blast on Friday morning. The town is home to a swathe of beachfront resorts as well as a royal palace.
Police and Thai media reported other blasts in the southern cities of Phuket, Trang and Surat Thani.
Tourist Shane Brett told Australian Broadcasting Corporation from his hotel room in Hua Hin that there was panic after the first explosion, which police said killed one Thai woman and wounded about 20 others, half of them foreigners.
"I was at a bar in the main bar district in Hua Hin right outside the Hilton Hotel and at first I heard kind of a bang and everyone kind of panicked," Brett said.
He looked outside the bar and said he saw people running. Half an hour later, he made it back to his hotel. On the way, he said he saw "a good few people injured and the whole area just panicking ... the whole area was just shut down with police cars, ambulances".
Thursday's bombs were set off by remote control, half an hour apart, according to General Sithichai Srisopacharoenrath, the police superintendent in Hua Hin, and his deputy, Lt Gen Samer Yousamran.
Sithichai said both devices were hidden inside plants on a street filled with restaurants, bars and food sellers that is popular with tourists and residents. He said a mobile phone had been recovered that they believed was used to detonate at least one of the bombs.
Thursday's fatality was reported to be a woman street food seller and several of the injured were reportedly in a serious condition. Lt Chaiyot Tisawong, an officer in Hua Hin, said 10 of the injured were foreigners. Their nationalities were not immediately known.
On Friday morning, two more bombs exploded in Hua Hin, killing one person and wounding four, police said.
Another pair of bombs exploded in front of two police stations half an hour apart in Surat Thani in southern Thailand.
Earlier on Thursday, another bomb blew up in the southern province of Trang, killing one person and injuring six, according to Thai news reports.
Trang is on the fringes of Thailand's deep south, where a low-level Muslim separatist insurgency had killed more than 5,000 people since 2004. Almost all the violence has been in the three southern-most provinces.
Col Krisana Patanacharoen of the Royal Thai Police said it was too soon say who was behind the attacks but "we are sure that it is not linked to terrorism".