There are 14,000 to 15,000 American military personnel in the country.
No other American personnel observed the launch either, the officials said.
Currently, there are fewer than 100 American military personnel here.
"Would that by any chance be an American military personnel you knew about for more than a year and didn't tell us?"
By 1964, there were 23,000 American military personnel in the country.
The total number of American military personnel in the region appears to be well over 200,000.
It was not clear if American personnel were inside the vehicles.
American military personnel said today that the trip was routine.
Many of these people, if they ever were American military personnel, are likely retired.
The families of American personnel pay in tension and separation.