North Korea denies artillery firing and mocks South Korea's detection capabilities.

The influential sister of North Korean leader Kim Jong Un has mocked South Korea’s ability to detect weapons launches by the North

SEOUL, South Korea -- The influential sister of North Korean leader Kim Jong Un mocked South Korea’s ability to detect weapons launches by the North on Sunday, as she denied Seoul’s claim that North Korea fired artillery shells into the sea the previous day.

South Korea's military quickly dismissed her statement as “a low-level psychological warfare" and warned that it will make a stern response to any provocations by North Korea.

South Korea’s military earlier said North Korea fired shells near the rivals’ disputed western sea boundary for a second consecutive day on Saturday. The military said North Korea fired more than 60 rounds on Saturday, a day after launching more than 200 shells.

North Korea acknowledged it performed artillery firings on Friday but said it didn’t fire a single round on Saturday.

Kim’s sister, Kim Yo Jong, said Sunday that North Korea only detonated blasting powder simulating the sound of its coastal artillery at the seashore to test the South Korean military’s detection capabilities.