North Korea on Tuesday warned that US-South Korea military drills to be held next month "will affect" proposed working-level nuclear talks between Pyongyang and Washington.

It was the first statement from Pyongyang on the issue since US President Donald Trump and North Korean leader Kim Jong Un agreed at an impromptu meeting in the Demilitarized Zone to resume stalled denuclearisation talks.

"While efforts are underway to arrange working-level talks between North Korea and the US in the wake of the top-level meeting at Panmunjom, the US is planning the joint 19-2 Dong Maeng military exercise," an unnamed spokesperson of the foreign ministry said in a statement carried by state news agency KCNA.

"If realised, it will affect the working-level talks."