SEOUL, South Korea -- North Korea fired suspected artillery into the sea Sunday, South Korea's military reported. This was days after North Korean leader Kim Jong Un demanded a greater defense capability to deal with threats from outside.

The South Korean Joint Chiefs of Staff stated in a statement that they detected flight paths believed to be North Korean artillery Sunday morning. The Joint Chiefs of Staff stated that South Korea is maintaining a strong military readiness, in close coordination and with the United States due to increased surveillance on North Korea.

According to South Korea's presidential offices, officials from South Korea raised concerns that North Korea was upgrading its weapons systems and threatened South Korea during a meeting of the national security council. They also vowed to sternly confront such North Korean efforts.

Outside attention is less drawn to the North's artillery launches than its missile launches. However, the North's forward-deployed long range artillery guns pose a serious security risk to South Korea's metropolitan area. It is located only 40-50 km (25-30 mi) from North Korea's border.

These artillery shots are the latest in a series of weapons tests North Korea has conducted this year. Experts believe it was an attempt to press its rivals Washington, Seoul, to ease international sanctions against Pyongyang.

Officials from the U.S. and South Korea recently stated that North Korea was close to completing preparations for its first nuclear attack in five years. In violation of the 2018 moratorium on large missile tests, North Korea launched an intercontinental missile capable of reaching America's mainland.

Kim spoke at a meeting of the ruling party last week and stressed the need to increase his country's military capabilities, stating that the current security situation is "very serious".

State media did not report on the United States and South Korea in Kim's speech. He still outlined "militant tasks" that his armed forces would undertake, suggesting that he would continue with his high-profile plans for arm buildup.

North Korea could conduct a seventh nuclear test. Experts believe that North Korea will use the test to make warheads for tactical nuclear weapons to hit targets in South Korea.