The United States on Friday announced a $1.1 billion arms package for Taiwan, vowing to keep boosting the island’s defenses as tensions soar with Beijing, which warned Washington of “counter-measures.” The sale comes a month after House Speaker Nancy Pelosi defiantly visited the self-governing democracy, prompting mainland China to launch a show of force that could be a trial run for a future invasion. The package — the largest for Taiwan approved under President Joe Biden’s administration — includes $665 million for contractor support to maintain and upgrade a Raytheon early radar warning system in operation since 2013 that would...