South Korea's health ministry on Wednesday said two more people have died in its Middle East Respiratory Syndrome (MERS) outbreak and reported 13 new cases, taking the total to 108.

The two deaths, both cancer patients, bring the number of fatalities to nine. All of those who died had been suffering serious ailments before they tested positive for the MERS virus, the ministry said.

The 13 new cases were all linked to hospitals, it said.

South Korea's infections have all been traced to a man who developed MERS after returning from a trip to the Middle East in early May, and who came into contact with other patients at a hospital before being diagnosed.

The outbreak has caused public alarm with more than 2,200 schools closing or cancelling classes. Around the region some countries have issued advisories against travel to SouthKorea or stepped up screening of inbound passengers.

The World Health Organization (WHO), which began work on Tuesday on a joint mission with South Korea to analyze the virus and review the country's response, has yet to recommend any curbs on travel or trade with South Korea.

South Korea's new cases bring the total number of MERS cases globally to 1,257 based on WHO data, with at least 448 related deaths. The country has the second highest number of cases after Saudi Arabia, according to the European Centre for Disease Prevention and Control.