TOKYO—Japan’s Cabinet on Friday approved a 770 billion yen ($6.8 billion) request for an extra defense budget through March to expedite the purchase of missiles, anti-submarine rockets, and other weapons amid rising concern over the escalation of military activities by China, Russia, and North Korea. The request, still pending parliamentary approval, brings Japan’s military spending for the current year to a new high of more than 6.1 trillion yen ($53.2 billion), up 15 percent from 5.31 trillion yen in 2020. The Defense Ministry says its “defense power reinforcement and acceleration package” is designed to speed up deployment of some of the key equipment from the 2022 budget request. The goal is to beef up Japan’s defenses against North Korea’s missile threat and China’s increasingly assertive maritime activity around remote Japanese southwestern islands, officials said. Japan has also raised concerns over recent joint military activities by China and Russia near its …