North Korean soldiers crossed the border into South Korea, and South Korean soldiers fired warning shots.
This happened in a special zone called the Demilitarized Zone (DMZ), which is supposed to be a peaceful area.
North Korea has been sending garbage balloons into South Korea, and South Korea has started playing loudspeakers that North Korea doesn't like.
North Korea is worried that these broadcasts could make its soldiers and people unhappy and weaken its leader's power.
