The move comes as South Korea and the United States are holding their joint military exercises, which Pyongyang sees as preparations for an invasion.
Kwon Ki-joon, a spokesman for the South Korea Defense Ministry spokesman, said "several projectiles" flew about 1,000 kilometers (620 miles).
The firing took place in Tongchang-ri, in the country's North Pyongan province, and the projectiles are believed to have landed in the Sea of Japan, which is also known as the East Sea, according to a South Korean Defense Ministry official.