Story highlights

NEW: At least four people killed, more than 30 injured

Not clear if blasts are connected

Police say no international terrorism links

Bangkok CNN  — 

At least six explosions hit two Thai cities in a span of about 12 hours, police officials told CNN.

At least four Thai nationals have been killed and about 36 others were injured, including 10 foreigners, according to Anurak Amornpetchsathaporn with the Ministry of Public Health.

No one has claimed responsibility for the blasts, and it’s not clear if the bombings are connected.

Thai police say there’s no evidence the attacks are related to international terrorism.

“These incidents are different from the usual terrorism acts. They are more local sabotage on certain locations and provinces,” Deputy Police Spokesman Maj. Gen. Piyapan Pingmuang said at a news conference Friday.

Political unrest has in recent years roiled Thailand, resulting at times in protests. The series of blasts comes days before the first anniversary of the Erawan Shrine bombing, which killed 20 people, and five days after the country voted on a new constitution.

Pingmuang said the explosions are not linked to the Erawan bombing.

Following his weekly address to the nation, Thai Prime Minister Prayut Chan-o-cha denounced the blasts, telling the country – and the world – that the perpetrators will be brought to justice.

“I express my condolences to those deaths and injuries – both Thais and foreigners,” he said. “My government will take care and provide full support and we will investigate on this and bring those behind these attacks to legal prosecution with our best ability.”

The prime minister also called on the public to remain vigilant and exercise caution while visiting tourist hotspots, reminding locals to report anything unusual to officials immediately.

“All Thais must help each other unitedly to achieve stability and safety,” Chan-o-cha added, referring to the recent political turmoil following the constitutional referendum. “We won’t create any conflicts with anyone., we must not blame each other. Thais must be united as one.”

Thursday’s blasts

The first explosion occurred at 3 p.m. local time in Trang province, killing one man and injuring six people, according to the Royal Thai Police.

Two bombs went off that evening in the resort city of Hua Hin – one at 10:15 p.m. near a bar called Johnny’s 56, and another at 11 p.m. in front of the Rain Tree Spa.

A woman working at a food vending cart was killed, Police Lieutenant Colonel Samoer Yoosumran said.

Royal Thai Police said another 21 people were wounded.

They include citizens from Italy, Germany, the Netherlands and Austria, according to Thomas