Feb. 22 (UPI) -- Resilient Shield 2021, a computer-based drill involving the United States and Japan, began on Monday, a week after Chinese ships trespassed in Japanese waters.
The exercise is focused on U.S. naval tactics, techniques and procedures for ballistic missile defense, or BMD, and making sure that Japanese and U.S. forces are well-rehearsed at their execution, the Navy said Monday in a press release.
The annual event this year involves over 77 command centers of the U.S. Navy and the Japan Maritime and Air Self-Defense Forces in a four-day exercise, Navy officials said.
The Navy's 7th Fleet headquarters at Yokosuka, Japan, is the lead command center.
"Resilient Shield provides U.S. and Japanese watch-standers a unique opportunity to refine theater BMD tactics, techniques and procedures and build bilateral capabilities essential to regional missile defense," Cmdr. Jeremy Carlson, commanding officer of the Navy destroyer USS Benfold, said Monday in a press release.
Military collaborations between the United States and Japan are frequent.
In February, the U.S. Navy announced the completion of a nine-day mine warfare exercise off the Japanese coast designed to increase mutual proficiency in mine countermeasure operations.
Resilient Shield 2021 comes at a time of heightened tension in the region.
Ships of the Chinese coast guard entered the East China Sea in waters claimed by Japan near the disputed Senkaku or Diaoyutai Islands last week. The vessels traveled into an area near Minami-kojima, part of the Senkaku chain, before departing the area after Japanese coast guard units arrived.
China and Japan both claim the islands and have clashed over territorial claims, and Tokyo lodged a protest over the incident.
On Feb. 10, the White House revealed that U.S. President Joe Biden spoke by telephone with Chinese President Xi Jinping, with China's "increasingly assertive actions in the region" a topic of discussion.