SEOUL/BANGKOK (Reuters) -- South Korea reported three new cases of Middle East Respiratory Syndrome on Sunday, bringing the total to 169 in the largest outbreak outside Saudi Arabia, but Thailand said it had no new infections.

South Korea's Health Ministry late on Saturday reported the 25th fatality, a patient who had suffered a heart ailment and diabetes. The outbreak was first confirmed on May 20 but seems to have leveled off, the ministry said on Friday.

Thailand, which discovered its first case last week, says 175 people were exposed to its single patient, with no new infections reported so far.

8 PHOTOS MERS (Thailand ONLY) See Gallery South Korea reports 3 new MERS cases, Thailand says none A security guard wearing a face mask stands on a train platform as commuters board a train in Bangkok on June 19, 2015. Thailand on June 18 said a 75-year-old man from Oman was confirmed to have MERS in Southeast Asia's first case of the virus since an outbreak in South Korea that has killed 23 people. AFP PHOTO / Christophe ARCHAMBAULT (Photo credit should read CHRISTOPHE ARCHAMBAULT/AFP/Getty Images) A man wearing a face mask hands food to a customer at his road side stall in Bangkok on June 19, 2015. Thailand on June 18 said a 75-year-old man from Oman was confirmed to have MERS in Southeast Asia's first case of the virus since an outbreak in South Korea that has killed 23 people. AFP PHOTO / Christophe ARCHAMBAULT (Photo credit should read CHRISTOPHE ARCHAMBAULT/AFP/Getty Images) A man wearing a face mask prepares food at his road side stall in Bangkok on June 19, 2015. Thailand on June 18 said a 75-year-old man from Oman was confirmed to have MERS in Southeast Asia's first case of the virus since an outbreak in South Korea that has killed 23 people. AFP PHOTO / Christophe ARCHAMBAULT (Photo credit should read CHRISTOPHE ARCHAMBAULT/AFP/Getty Images) A woman wearing a face mask prepares food at a market in Bangkok on June 19, 2015. Thailand on June 18 said a 75-year-old man from Oman was confirmed to have MERS in Southeast Asia's first case of the virus since an outbreak in South Korea that has killed 23 people. AFP PHOTO / Christophe ARCHAMBAULT (Photo credit should read CHRISTOPHE ARCHAMBAULT/AFP/Getty Images) An Airports of Thailand employee (L) monitors a screen as travelers walk past a thermoscan checking their body temperature upon their arrival at Bangkok's Suvarnabhumi Airport on June 19, 2015. Thai authorities on June 19 said two relatives of an Omani man found to have MERS were being tested for the deadly virus in the kingdom. Thailand, a booming medical tourism hub popular with Middle Eastern patients, Thursday confirmed the Omani, 75, had MERS, days after he arrived at a Bangkok hospital for treatment for a heart condition. AFP PHOTO / Christophe ARCHAMBAULT (Photo credit should read CHRISTOPHE ARCHAMBAULT/AFP/Getty Images) Airports of Thailand employees wear face masks as they wait for travelers to walk past a thermoscan checking their body temperature on arrival at Bangkok's Suvarnabhumi Airport on June 19, 2015. Thailand on June 18 said a 75-year-old man from Oman was confirmed to have MERS in Southeast Asia's first case of the virus since an outbreak in South Korea that has killed 23 people. AFP PHOTO / Christophe ARCHAMBAULT (Photo credit should read CHRISTOPHE ARCHAMBAULT/AFP/Getty Images) A woman wearing a face mask uses an escalator to reach a train platform as she commutes in Bangkok on June 19, 2015. Thailand on June 18 said a 75-year-old man from Oman was confirmed to have MERS in Southeast Asia's first case of the virus since an outbreak in South Korea that has killed 23 people. AFP PHOTO / Christophe ARCHAMBAULT (Photo credit should read CHRISTOPHE ARCHAMBAULT/AFP/Getty Images) A Thai man holds his child while walking past an information banner on Middle East Respiratory Syndrome (MERS) at the entrance of Bamrasnaradura Infectious Diseases Institute in Nonthaburi province on June 19, 2015. Thailand on June 18 said a 75-year-old man from Oman was confirmed to have MERS in Southeast Asia's first case of the virus since an outbreak in South Korea that has killed 23 people. AFP PHOTO / Pornchai KITTIWONGSAKUL (Photo credit should read PORNCHAI KITTIWONGSAKUL/AFP/Getty Images) Up Next See Gallery Discover More Like This HIDE CAPTION SHOW CAPTION of SEE ALL BACK TO SLIDE

"We can confirm that there are no new MERS patients," said Health Minister Rajata Rajatanavin as he led reporters on a tour of Bangkok's Suvarnabhumi airport to show health and safety measures that have been put in place, including thermoscans for passengers.

Bangkok is one of the region's main aviation hubs and tourism accounts for 10 percent of the Thai economy. Thai tourism minister Kobkarn Wattanavrangkul said tourism had not been hit.

MERS was first identified in humans in Saudi Arabia in 2012 and the majority of cases have been in the Middle East. Scientists are not sure of the origin of the virus, but several studies have linked it to camels.

Isolated cases have cropped up in Asia before South Korea's outbreak.

Global Outbreaks: MERS | HealthGrove

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