The military has heightened its alert against swine flu as health officials reported the first suspected case of the contagious disease in South Korea, according to Yonhap News Agency.
The country operates 655,000 soldiers, one of the largest forces in the region. Quarantine officials said earlier in the day that a civilian who recently returned from Mexico is being tested for the virus that is spreading worldwide at a faster-than-expected pace.
"Military authorities have ordered that any soldier suspected of having flu symptoms be reported to them immediately," Won Tae-jae, spokesman for the Ministry of National Defense, was quoted as saying.
"The ministry has also ordered officers to refrain from traveling abroad," he said, adding no cases of contraction by a soldier have been reported yet.
About 150 people are believed to have been killed in Mexico by the type A influenza virus that breaks out among pigs and is transmittable to humans.
The United States, Canada and some European countries have also reported human cases of the flu, which has forced the World Health Organization to raise its alert level to the third highest.
South Korea plans to double its stockpile of Tamiflu and other influenza drugs, enough to treat 5 million people, around 10 percent of the country's population.