Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources. Newsweek AI is in beta. Translations may contain inaccuracies—please refer to the original content. China is set to debut at least two of its unmanned underwater vehicles (UUVs) during a military parade as the country's sea power gap with the United States continues to narrow. Why It Matters The preparations come as the People's Liberation Army Navy, the world's largest by hull count, steps up efforts to challenge U.S. primacy in the Western Pacific. Washington and its allies fear China will increasingly…