North Korea appears to have made some progress in developing its intermediate-range Musudan missile after a series of embarrassing failures earlier this year, the Defense Ministry said after Pyongyang tested-fired two of the missiles Wednesday.

The Defense Ministry said the North fired the first Musudan — which could reach as far as Guam — from the eastern coastal city of Wonsan at around 5:57 a.m. That missile burst into pieces and fell into the sea.

South Korea's Joint Chief Staff said that launch was assumed to be a failure, and Japanese Defense Minister Gen Nakatani also hinted that it was unsuccessful, saying "there seems to have been fundamental technical problems with the missile and its engine."