South Korea has raised its Middle East Respiratory Syndrome (MERS) alert level by one notch following the outbreak of the country's first MERS case in three years.

The government on Sunday raised the alert from the lowest "blue" to "yellow" or "watch" after a 61-year-old man was diagnosed with the highly infections respiratory disease on Saturday.

The Korea Centers for Disease Control and Prevention (KCDC) also set up a central quarantine headquarters to prevent the spread of the disease.

The KCDC said that 21 people who have been confirmed to have come in close contact with the infected man were quarantined and are being monitored by relevant local health centers.

The government also notified 17 cities and provinces of the hiked MERS alert and ordered them to operate their own local quarantine teams.