South Korea recorded its sixth death and biggest single day jump in Middle East Respiratory Syndrome (MERS) infections Monday, with 23 new cases in the largest outbreak of the potentially deadly virus outside Saudi Arabia.

South Korea recorded its sixth death and biggest single day jump in Middle East Respiratory Syndrome (MERS) infections Monday, with 23 new cases in the largest outbreak of the potentially deadly virus outside Saudi Arabia.

From just four cases two weeks ago, the total number of infections now stands at 87, including six people who have died.

The latest fatality was an 80-year-old man who died Monday morning in a hospital in Daejeon, 140 kilometers (87 miles) south of Seoul.

The outbreak has triggered widespread public concern in South Korea, with 2,300 people placed under quarantine orders and nearly 1,900 schools -- mostly in Seoul and surrounding Gyeonggi province -- closed down.

Among the 23 new cases, 17 were infected at the Samsung Medical Centre in southern Seoul, the health ministry said.

One of them was a 16-year-old student hospitalized on May 27 for another disease, the education ministry said, in the first case involving a teenager.

Given the period of time he had been in hospital, the ministry stressed it was "not possible" that he had infected any classmates at school.

All the infections so far have been restricted to hospitals, with transmissions between patients, staff and their families.