What press conference?
CNN, LA Times, etc.. many US news sources are just trying to scare people. They don't give a crap about people who are directly effected or people who are connected to those who are effected, etc... They just don't care about accuracy or responsibility. They just report news for the sake of shock value.
If I were a Japanese Government official or Japanese media liaison, the LAST people I would give sensitive information to is the Americans.