Reuters reported that South Korea and Japan said North Korea fired a ballistic missile into the sea early Saturday, 11 Mehr. The launch took place after Pyongyang rejected Seoul’s request for an apology over an explosion of border mines that wounded two South Korean soldiers.

The South Korean military said the missile was launched at around 6:30 a.m. from the Wonsan area and traveled more than 700 kilometers. Seoul and Washington are reviewing details of the test. Japan also said the object launched was likely a ballistic missile.

After the launch, South Korea’s National Security Council held an emergency meeting, and the country’s military increased monitoring to identify any possible subsequent tests.

Reuters wrote that the test was carried out one day after Kim Yo Jong, the sister of Kim Jong Un, the North Korean leader, rejected a request for an apology over the mine explosion in a non-military area.

North Korea has conducted more than 10 missile tests since the beginning of the year. Relations between the two Koreas have worsened in recent years, and Pyongyang has called South Korea its “main enemy.”