Story highlights One woman killed in Friday morning bombing in Thailand's south

Thai woman dead, foreign tourists injured in Hua Hin, says official

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

Two bombs went off in the resort of Hua Hin Friday morning near the clock tower, a city landmark, according to Police Lieutenant Colonel Samoer Yoosumran.

Thailand bombings Thursday night, Hua Hin -- Twin blasts strike near bar at about 11 p.m., killing at least one Friday morning, Surat Thani -- Two explosions occur, the first at 8:01 a.m. and the second at 8:30 a.m., killing at least one Friday morning, Phuket -- Two bombs went off at Patong beach and Bangala street at 9 a.m., injuring one Friday morning, Hua Hin -- Two more bombs hit at 9:05 a.m. near a clock tower Source: Thai police and military All times are local

"The bombs went off while we were working on site, they were not very far from each other," Yoosumran said. "Police have tightened security. We have set up check points and inspecting bags and other things."

Around 650 feet (200 meters) away, another two bombs exploded late Thursday as foreign tourists were leaving local bars to go back to their hotels, Yoosumran said.

At least 11 people -- mostly foreign visitors -- were injured and a woman who had a food vending cart in front of a bar was killed Thursday night, according to Yoosumran.

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