SEOUL: North Korea fired at least one ballistic missile, Seoul's military said Saturday, a day after Pyongyang called the South "despicable" for demanding an apology over a blast in the demilitarised zone that wounded three of its soldiers.

"Our military detected a ballistic missile launched from the Wonsan area of North Korea toward the East Sea," Seoul's Joint Chiefs of Staff said, referring to the body of water also known as the Sea of Japan.

Pyongyang has denied being behind the landmine blast last month inside the Demilitarised Zone (DMZ), the heavily mined buffer dividing the two Koreas since their 1953 armistice.

Seoul as well as the US-led United Nations Command said the blast was caused by North Korean mines laid on the South Korean side of the border.