US reconnaissance planes take off from Japan
US intelligence-gathering aircraft have been taking off from an American air base in southern Japan, a day after North Korea said it tested a hydrogen bomb.
At least three planes departed Thursday from Kadena Air Base on the Japanese island of Okinawa.
It wasn't clear what they were doing, but they could be involved in trying to determine what kind of nuclear device North Korea detonated.
One of the aircraft seen departing, the RC-135S, collects optical and electronic data from ballistic targets. It is used for arms treaty compliance verification and US strategic and missile defense development.
