TOKYO (AP) – Japan confirmed its first three swine flu cases, a quarantine official said Saturday.

The three were among about 390 passengers who arrived at Tokyo’s Narita International Airport on a flight from Detroit, an airport quarantine official said on condition of anonymity, citing department rules.

They have been identified as two high school students and a teacher who had visited Canada on a school trip.

All three were quarantined after showing flu symptoms and tested positive in a primary test on the plane, the official said. They are recovering at a hospital near the airport.

The two teenage boys and the male teacher had visited Canada’s Ontario province on a home stay program with about 30 other students, public broadcaster NHK reported.

Airport quarantine officials are examining other passengers seated near the patients as a precaution, the official said.