Manila, Philippines—The Philippine and US militaries on Monday kicked off three weeks of joint exercises that will simulate a "full-scale battle scenario," as the two allies seek to deter Beijing's ambitions in the disputed South China Sea. Around 17,000 troops are expected to take part in the annual "Balikatan," or "shoulder-to-shoulder" drills, which for the first time will include an integrated air and missile defence simulation to be attended by President...