North Korea fired multiple cruise missiles toward the sea off its west coast on Wednesday, South Korea's Joint Chiefs of Staff said.
The missiles were fired at around 7 a.m. (2200 GMT on Tuesday) and were being analyzed by South Korean and US intelligence, the JCS said in a statement.
Further activities by the North were being monitored, the JCS added.
Tensions have spiked on the Korean peninsula following intensifying military maneuvers by the South Korean and US militaries in response to weapons testing by the North
The latest firing of missiles comes after Pyongyang said it tested a solid-fuel hypersonic missile with intermediate-range earlier this month in a move that was condemned by the United States, South Korea and Japan.