SEOUL, Aug 4 (AP) - South Korean police have detained a man suspected of stabbing a high school teacher with a knife on Friday (Aug 4) in the city of Daejeon.

The stabbing follows a separate, apparently random attack on Thursday in which 14 people were wounded near a busy subway station in Seongnam.

Officials at the Daejeon Metropolitan Police Agency did not immediately release the personal details of the suspect in the Friday morning attack on the teacher at Songchon High School, describing him only as a man in his late 20s.

According to police, the suspect waited for the teacher to step out of a classroom before stabbing him and fleeing the scene, which, according to officials, suggests they were acquaintances.

Police and fire department authorities did not specify the teacher’s condition.

The attack in Daejeon, about 120km south of Seongnam, came hours after President Yoon Suk-yeol called for “ultra-strong” law enforcement measures to restore faith in public safety after Thursday’s violence, which he described as a “terrorist attack on innocent citizens”.

At least two people were in life-threatening conditions after Thursday’s attack in Seongnam, in which a car rammed onto a sidewalk before the driver stepped out and began stabbing people at random at a shopping mall linked to the Seohyeon subway station at the heart of a bustling leisure and business district.

Among the five people who were hurt by the car, at least two were hospitalised in critical condition. Among the nine who were stabbed, eight were being treated for serious injuries, according to Gyeonggi Province fire department officials.

Police are questioning the 22-year-old suspect. They did not identify the suspect or offer any immediate information about a potential motive.

During police interviews, the suspect talked incoherently and said he was being stalked by an unspecified source, said Park Gyeong-won, an official at Gyeonggi’s Bundang district police station.

The suspect purchased the two knives he used in the stabbings from a different shopping mall on Wednesday, Park said, but there isn’t clear evidence he planned the attack in advance.

Photos from the scene showed forensic units examining the halls of the AK Plaza, where the attack took place Thursday. A white Kia hatchback with a broken front window and ruptured front tire could be seen on a sidewalk near the subway station.

A witness named Hwang Hee-woon told YTN television that he “heard a sound from the first floor that seemed like a scream, so customers and shop workers were gathering on the rails of the second floor near the escalator to see what was happening below”.

“Suddenly, someone told us the person who committed the crime was coming up to the second floor, so we ran away in panic,” he said. He ended up hiding inside a refrigerated storage room with some mall employees.

Thursday’s attack was the country’s second mass-stabbing case involving random targets in a month.

In July, a knife-wielding man stabbed at least four pedestrians on a street in the capital, Seoul, killing one person. Attacks by firearms are rare in South Korea, which tightly controls gun possession, but there aren’t meaningful restrictions applying to knives, including kitchen tools that are often used for attacks.