Japan will send Self-Defense Forces ( SDF) staff to observe a joint military drill between the United States and South Korea slated for Sunday through Wednesday in the Sea of Japan, the Defense Ministry said Friday.

Japan will not dispatch any vessel to the drill but several officers from the Maritime Self-Defense Force (MSDF) will attend the joint exercise as observers.

"The government has judged that sending the SDF staff as observers would not violate Japan's pacifist Constitution", Kyodo news agency said in a report.

South Korea and the United States have agreed to stage a series of joint naval and air drills in the Sea of Japan and the Yellow Sea, which the White House said are "defensive in nature" and are designed to send a "signal of deterrence" to the Democratic People 's Republic of Korea (DPRK) following the sinking of a South Korean warship in March with a loss of 46 sailors.

A South Korean-led international investigation blamed DPRK for sinking Cheonan with a torpedo but the latter denied any involvement.

China has expressed concern over the joint military exercises, urging relevant parties to exercise calm and refrain from acts that might escalate tension in the region.

The first joint drill involving the U.S. nuclear-powered aircraft carrier USS George Washington will come July 25 in waters off the east coast of the Korean Peninsula, and the two allies plan to stage more drills down the road in both the Yellow Sea and the Sea of Japan.