MISAWA AIR BASE, Japan — U.S. Forces Japan officials on Monday ordered any Misawa base resident who traveled from the United States in the last 10 days to be tested for swine flu.

Few details were available late Monday night as to why Misawa community members were under such sudden scrutiny.

The order was broadcast on the local American Forces Network channel in "response to guidance we received from USFJ," according to Misawa spokeswoman Staff Sgt. Kelly White.

USFJ officials could not be contacted late Monday night for comment.

But when queried earlier Monday on local rumors of a possible case, USFJ spokeswoman Air Force Maj. Denise Kerr said there were no confirmed swine flu cases on any U.S. military base in Japan.

The USFJ announcement came as the total number of swine flu cases in Japan jumped to more than 120, according to The Associated Press.

Japanese officials confirmed at least 121 people have tested positive for the H1N1 virus, according to an Associated Press report on Monday.

According to the AP report, Japan is the fourth-most infected country.

Earlier this month, a 4-month-old infant and the child’s mother were quarantined after arriving at Yokota Air Base, Japan, because the infant had a fever. Thirteen passengers sitting near the infant were voluntarily quarantined until testing on the woman and infant proved negative.

USFJ officials have said that they will continue to screen passengers arriving from the States to U.S. bases in Japan, just as Japan is doing at international airports to try to prevent swine flu from entering the country, the spokesman said.