North Korea said it test-fired four strategic cruise missiles toward the Sea of Japan on Wednesday.

It said the missiles were launched from South Hamgyong Province in the country's east.

The North also said it conducted a new underwater weapon test on Tuesday. It said what it called an "underwater nuclear attack drone" cruised for 59 hours at a depth of 80 to 150 meters in the Sea of Japan.

The country claimed the drone detonated underwater in an area set as a mock enemy port.