TOKYO — Defense Secretary Pete Hegseth on Wednesday said China’s large-scale military buildup and aggressive actions pose a “severe” threat to the U.S. and its key ally Japan . Following meetings with the new Japanese Defense Minister Shinjiro Koizumi , Mr. Hegseth said building up forces and defenses to counter the danger is an urgent priority. “As the minister and I discussed today, the security situation around Japan and in the region remains, as he said and we agree, severe,” Mr. Hegseth