Barack Obama headed to Seoul Friday on the second leg of a tour of Asia, as new satellite images suggested North Korea was readying to stage a nuclear test in defiance of world opinion.
Pyongyang´s apparent push could further complicate his visit to a country raw with emotion, where around 300 people are dead or missing after a ferry carrying hundreds of school children capsized last week.
The US president is expected to offer personal condolences to his South Korean counterpart Park Geun-Hye over the tragedy.
