A grenade exploded at an Army recruit training center in Daegu on Friday, killing one instructor and injuring two other soldiers, military officials said.

The incident took place at 11:08 a.m. as a 20-year-old trainee, identified only by his surname Sohn, was preparing to throw a K413 hand grenade right after removing its safety hook.

A 27-year-old sergeant surnamed Kim who was giving guidelines in the same trench was immediately hospitalized to treat shrapnel wounds all over his body but died at 12:53 p.m., officials said.

The blast also severed Sohn’s right wrist. He underwent surgery at Kyungpook National University Hospital.

Another 27-year-old sergeant surnamed Park, who was about 1 meter away from the recruit, also suffered injuries to his left leg, said Maj. Gen. Koo Hong-mo, head of operations at the Joint Chiefs of Staff.

“The grenade detonated in the trainee’s hand just when he was about to hurl it,” Koo said during a parliamentary audit later in the day. 

Some other 200 soldiers were at the site for their fourth week of training, but no one else was hurt, he noted.

The military has launched an investigation to examine if the device was faulty and how the incident happened.

The K413 is an upgrade to the Korean-made K400 fragmentation grenade, which went off at a boot camp last September in Pohang, North Gyeongsang Province, killing three.

Yet the new model showed poor performance during a regular ammunition test conducted in April 2014 by the Army as six out of 30 units exploded before the three-second threshold, according to Rep. Kim Kwang-jin of the main opposition New Politics Alliance for Democracy, citing documents submitted by the Army and the Defense Agency for Technology and Quality.

Though the DTaQ determined that the premature blast resulted from manufacturing defects after a seven-month-long analysis, the military recalled only 60,000 units produced in 2011. About 1 million K413s have been delivered since 2010, with the current inventory standing at around 250,000, the lawmaker said.

“Given the discovery of the flaws, the military should halt the use of the grenade and consider retracting all existing ones at least until the exact cause of the incident comes to light,” Kim said.

The explosion in Daegu is the latest in a string of military accidents involving firearms, land mines and other weapons.

In November 2008, a blast occurred within a guard post in Cheorwon County, Gyeonggi Province, after a private broke the return rule and threw a grenade in a barrack where 16 other servicemen were asleep. The incident wounded five.

In South Korea, all physically able young men are subject to compulsory military service for about two years, after which they are required to receive six rounds of three-day training over a period of eight years.

By Shin Hyon-hee (heeshin@heraldcorp.com)