Seoul, Jun 6 (IANS): South Korean President Yoon Suk-yeol on Monday vowed to respond firmly and sternly to any North Korean provocation as Seoul and Washington fired missiles in response to the Pyongyang's missile launches the previous day.

Yoon made the remark during a Memorial Day ceremony held at Seoul National Cemetery, a day after North Korea fired eight short-range ballistic missiles (SRBM) into the East Sea in its third show of force since the President took office last month, reports Yonhap News Agency.

"Even at this moment, North Korea's nuclear and missile threats are getting sophisticated," he said, referring to Sunday's tests.

"North Korea's nuclear and missile (programs) are reaching the level of threatening not only peace on the Korean Peninsula but also in Northeast Asia and the world."

Yoon said his administration will deter the nuclear and missile threats while also building a "more fundamental and practical security capability".

"Our government will respond firmly and sternly to any North Korean provocation," he said. "We will make sure there isn't a single crack in protecting the lives and property of our people."

Yoon has taken a tougher stance on North Korea than his predecessor, Moon Jae-in, whose attempts to build peace through talks with North Korean leader Kim Jong-un failed to stop the regime from advancing its weapons programs.

The President's remark came shortly after South Korea and the US launched the ground-to-ground Army Tactical Missile System (ATACMS) missiles from an eastern coastal region in Gangwon province starting at 4.45 a.m. for around 10 minutes.

North Korea's Sunday launches is presumed to have involved a variety of SRBMs, including the KN-23 missile modeleld after Russia's Iskander ballistic missile.

The KN-23 is known for its "pull-up manoeuver", designed to avoid interception.