Two senior U.S. figures apparently flew to Pyongyang aboard a U.S. Air Force plane in a secret mission six days before North Korea's failed rocket launch on April 13.
"At around 7:40 a.m. on April 7, a U.S. Air Force Boeing 737 entered North Korea," a diplomatic source in Seoul said. "The aircraft flew from Guam and into North Korea along the same route on the West Sea used by former President Kim Dae-jung during his visit to the North back in 2000."
Experts speculate that the plane carried Joseph Di Trani, a nuclear negotiator in the George W. Bush administration, and Sydney Seiler, a National Security Council advisor to U.S. President Barack Obama.
The secret visit appears to have been a last-ditch effort by Washington to stop North Korea from pressing ahead with the rocket launch.