(BSS/AFP) - South Korean President Lee Jae Myung urged North Korea on Thursday to return to dialogue, a day after Seoul`s military demanded an apology over a blast in the demilitarised zone that severely injured three South Korean soldiers.

Seoul and Pyongyang remain technically at war since the 1950-53 Korean War ended in a truce, not a peace treaty.

Three South Korean officers were severely injured in the September 21 explosion inside the Demilitarised Zone (DMZ), the heavily mined buffer dividing the two Koreas since their 1953 armistice. One lost his foot.

The powerful sister of North Korean leader Kim Jong Un on Wednesday denied North Korea was behind the landmine blasts.

On Thursday, however, Lee asked that Pyongyang return to dialogue.

"I hope that the North joins us now on the path of restoring trust and resuming dialogue, following a long interruption," Lee said in his speech marking the country`s Armed Forces Day.

A day earlier, Seoul`s military had demanded an apology from North Korea, claiming the incident was "a clear violation of the Armistice Agreement and undermines the spirit of existing inter-Korean agreements."