Photo/IllutrationThe aircraft carrier USS Carl Vinson transits the Sunda Strait between the Indonesian islands of Java and Sumatra on April 15. (The U.S. Navy via AP)

  • Photo/Illustraion

As Pyongyang approaches an important military anniversary, Maritime Self-Defense Force and U.S. Navy vessels linked up in a joint training exercise to keep the heat on North Korea.

The show of force apparently runs contrary to what is being seen in both South Korea and North Korea, where there are no obvious signs of the military ratcheting up preparations or defensive measures.

Along with the joint naval maneuvers sending a message to Pyongyang, Tokyo hopes China takes notice as well.

A strike force led by the nuclear-powered aircraft carrier USS Carl Vinson was joined by the MSDF's Ashigara and Samidare destroyers in waters in the western Pacific east of the Philippines on April 23, according to government sources.

The training exercise will last for a few days, and the fleet will sail north in the East China Sea to approach waters off Japan.

"The specific nature of the training maneuvers are not the issue," a Japanese government source said. "There is significance in showing North Korea the joint sailing of military ships from Japan and the United States."

April 25 marks the 85th anniversary of the founding of the Korean People's Army, which raised concerns in both Japan and the United States about some military provocation by Pyongyang to mark the occasion.

"While the situation has become very tense due to the provocations by North Korea, it is still far from being a state of war," said a high-ranking Defense Ministry official. "It is a so-called gray zone situation, and the framework for close cooperation between Japan and the United States is functioning extremely effectively."

The latest training maneuvers are being implemented under the framework of flexible deterrent options that were agreed to under the new Guidelines for Japan-U.S. Defense Cooperation, which were approved in April 2015.

Coordination for the exercise was conducted through the Alliance Coordination Mechanism that was also included in the new defense cooperation guidelines.

North Korea is not the only target of the joint exercise.

"It is also a countermeasure to the active military moves being made in the East China Sea and South China Sea by Beijing," another government source said.

Meanwhile, while the South Korean government is viewing the deployment of the Carl Vinson strike force as a means of applying pressure on North Korea, there are no signs of increased preparations in South Korea for a military conflict with its northern neighbor.

Moreover, military sources said North Korea had not ramped up its military preparations as of April 23 to the same level as in past incidents of heightened tensions between North Korea and the United States.

A source with close ties to North Korea also said there were no signs that Pyongyang would conduct a nuclear test as a provocation to mark the upcoming anniversary.

China is also trying to encourage restraint on the part of both its close ally North Korea and the United States.

"There have been too many words and deeds in recent days that have been based on a show of force as a means of demonstrating resistance," Chinese Foreign Minister Wang Yi said about the situation on the Korean Peninsula during a news conference on April 23 in Greece, where he was visiting.

"There is a need for peaceful and rational voices to be heard. China will continue to maintain dialogue with the various relevant nations in order to fulfill a constructive role in resolving the issue of nuclear weapons development."

(This article was compiled from reports by Takateru Doi in Tokyo, Yoshihiro Makino in Seoul and Daisuke Nishimura in Beijing.)