BANGKOK — A soldier shot multiple people in northeastern Thailand on Saturday, killing at least 16, and was holed up in a popular shopping mall, an emergency worker said.

Noppadol Sirijanya, a member of the Sawang Metta Tham Rescue Center in Nakhon Ratchasima, said the death toll reached 16 as of 10 p.m. Police had earlier said that more than 10 people had been killed.

It was unclear how many people were wounded. The authorities put nearby hospitals on alert and asked for blood donations. Public Health Minister Anutin Charnvirakul said on Facebook that a doctor was shot while helping an injured person.

It also was not clear whether the gunman had taken hostages inside the mall or how many people might still be inside.

Noppadol said a rescue team had successfully evacuated more than 100 people from the mall, where they had been trapped for hours. The center is a voluntary emergency aid organization that helps during accidents and disasters.

The shooter appeared to be armed with an assault rifle, based on security camera video aired on Thai Rath television. Thai Rath said the incident began at about 3:30 p.m.

A police officer contacted by phone in the city of Nakhon Ratchasima said the soldier initially shot dead another soldier and a woman and wounded a third person, apparently over a land dispute. Nakhon Ratchasima is also known as Korat.

City and neighborhood police officers, who asked not to be identified because they were not authorized to release information, said the man took a gun from his base and drove to the Terminal 21 Korat mall, shooting along the way. Several Thai media reported that he traveled in a military vehicle.

Video taken outside the mall and shared on social media showed people taking cover in a parking lot as gunshots were fired.

The mall was shut down and the street outside was closed while the authorities tried to arrest the gunman and rescue shoppers inside.

Defense Ministry spokesman Lt. Gen. Kongcheep Tantrawanich identified the suspect as Sgt. Jakrapanth Thomma. He said police and military units had locked down the mall and the surrounding area.

A video posted on social media from inside a car before all surrounding streets were shut down shows a man driving while a woman shouts, “What’s happening? Why are they running?”

Several gunshots are heard as they drive away from the mall, and the woman says, “Is it a robbery?”

The man believed to be the gunman posted updates to his Facebook page during the rampage with statements including “No one can escape death” and “Should I give up?” In a later post he wrote, “I have stopped already.”

His profile picture shows him in a mask and dressed in military-style fatigues and armed with a pistol. The background image is of a handgun and bullets.

In a photo circulated on social media that appeared to be taken from his Facebook page, the suspect can be seen wearing a green camouflaged military helmet while a fireball and black smoke rage behind him. The Facebook page was made inaccessible after the shooting began.

Nakhon Ratchasima is about 250 kilometers (155 miles) northeast of the Thai capital, Bangkok. It is a hub for Thailand’s relatively poorer and rural northeastern region.

Terminal 21 Korat is part of a small chain of Thai shopping centers run by Bangkok-based property developer LH Mall & Hotel Co. The malls feature floors modeled after major cities around the world.

The size of the mall could pose a challenge for security forces as they try to capture the gunman. It consists of seven main retail floors, including one below ground level, and scores of shops and restaurants. It also houses a movie theater on the top floor.

Many malls in Thailand, including Terminal 21’s namesake in Bangkok, have metal detectors and security cameras at entrances manned by uniformed but unarmed security guards. Checks on those entering are often cursory at best.

Gun violence is not unheard of in Thailand. Firearms can be obtained legally, and many Thais own guns. Mass shootings are rare, though there are occasional gun battles in the far south of the country, where authorities have for years battled a long-running separatist insurgency.

The incident came just a month after another high-profile mall shooting, in the central Thai city of Lopburi. In that case, a masked gunman carrying a handgun with a silencer killed three people, including a 2-year-old boy, and wounded four others as he robbed a jewelry store. A suspect, a school director, was arrested less than two weeks later and reportedly confessed, saying he did not mean to shoot anyone.