South Korea reported three new cases of Middle East Respiratory Syndrome Tuesday but no additional deaths from the potentially fatal disease.

With the latest cases, the total number of people diagnosed with the disease here came to 175, according to the Ministry of Health and Welfare. The country's death toll remained at 27.

Two of the three new patients came from those who have already been in isolation as suspected cases, while the source of infection for the third patient was still unclear, according to ministry officials.

They said the person may have been infected through an ambulance driver or a paramedic who had been exposed to MERS patients.

As of Tuesday, the number of people in isolation for possible infection came to 2,805, down from 3,833 on the previous day, according to the ministry.

Since the country reported its first MERS case on May 20, over

13,000 people have been subject to quarantine with 10,718 released from isolation after showing no symptoms of the disease for more than the known maximum incubation period of 14 days.

Those subject to isolation are currently banned from leaving the country.

To help prevent further spread of the disease in the country, the government said it has also placed a ban on the people subject to quarantine from using domestic air services.

"Starting from today, people subject to isolation for MERS are prohibited from using any domestic flight service in addition to international flights," the Ministry of Land, Infrastructure and Transport said in a press release.

The move comes after a male patient from Seoul was earlier found to have traveled to the southern resort island of Jeju, prior to his diagnosis but after developing symptoms of MERS.

Out of 175 people diagnosed with MERS so far, 54 have been discharged from the hospital following complete recoveries.

The MERS patients included a pregnant woman, who on Tuesday gave birth to a son through a caesarean section.

The 39-year-old patient had already recovered from the disease, but remained hospitalized as she was nearing her due date, according to ministry officials, who noted both the mother and her baby were in good health.

MERS is a viral respiratory disease first reported in Saudi Arabia in 2012.

There currently is no vaccine or treatment for the disease that had carried a very high fatality rate of over 40 percent until the outbreak here.

In South Korea, the fatality rate of the disease remains at around 15 percent. (Yonhap)