North Korea jammed GPS signals near the inter-Korean maritime border for the second day in a row on Thursday, according to South Korea’s Joint Chiefs of Staff (JCS), after the DPRK threatened military action if ROK ships crossed into its waters in the Yellow Sea.

Experts said it’s unclear whether North Korea conducted the GPS jamming to provoke a conflict but that it could use any accidental crossings of the sea border as a pretext for a military response.