According to reports, the missile landed close to the maritime border of the two countries for the first time since the division of Korea took place.

The short-range ballistic missile landed some 60km (37 miles) from the South's city of Sokcho and triggered air-raid alarms on Ulleungdo island, reports BBC.

Pyongyang fired at least 10 missiles "east and west" on Wednesday morning, the South Korean military was quoted as saying by BBC.

South Korea later fired three missiles in response to the North, the British media reported.

South Korea's military on Wednesday denounced North Korea's launch of its first missile into an area close to the South's territorial waters since the division of the peninsula more than seven decades ago and even called it an "intolerable" act.

"North Korea's missile launch, which marks the first time since the division of the peninsula that has landed near our territorial waters south of the Northern Limit Line, is very rare and intolerable," the  Joint Chiefs of Staff  said in a press release as quoted by Yonhap news agency.

"Our military vowed to respond firmly to this (provocation)," it added.

North Korea made the move at a time when the  United States and South Korea began their previously scheduled military exercises called “Vigilant Storm” on Tuesday.

Approximately 240 aircraft and thousands of service members from the ROK Air Force, U.S. Air Force, U.S. Marine Corps, U.S. Navy and U.S. Army will participate in this training, the US Department of Defence said in a statement.