The US and South Korea have continued to hold joint military exercises in Pohang as North and South Korea exchanged fires along their disputed western sea border.
The Ssang Yong exercise is part of annual exercises between the US and South Korea, which are reported to be the biggest by the US and South Korea since 1993.
Paul Kennedy, the Commanding General of the 3rd Marine Expeditionary Brigade, says the exercise is not aimed at any third party.
"This exercise was not designed to react to any political situation. It is not designed to send a message. This is something that we have to do, to be able to inter-operate with our allies."
Meanwhile, South Korea's Defense Ministry says that its military fired back on the north after North Korea's artillery shells fell south of their western sea border.
Reacting to the latest development on the Korean Peninsular, Chinese Foreign Ministry is urging "all relevant parties to maintain calm, exercise restraint and refrain from acts going against peace and stability".
Tensions have escalated on the Korean Peninsula after Pyongyang fired a volley of short- and medium-range missiles in recent weeks.
The North's recent missile launches came in protest against the joint annual war games between South Korea and the United States.
The UN Security Council has condemned the North's recent ballistic missile launches.
The North Korean Foreign Ministry says it will "not rule out a new form of nuclear test" to bolster up its nuclear deterrence in response to the UN's condemnation.
