A $6.5 billion deal to sell U.S. arms to Taiwan has ruined years of work building military trust with China, threatens Beijing's safety and ignores international law, REUTERS quoted the sources of the Chinese Foreign Ministry as saying on Tuesday. The U.S. government on Friday announced plans to sell a massive arms package to Taiwan, including 30 Apache attack helicopters and 330 Patriot missiles. The Pentagon's Defense Security Cooperation Agency told lawmakers that the sale would support Taiwan's continuing efforts to modernise its military, but Beijing said the deal was reckless, threatened national security and harmed a key diplomatic relationship. "For many years we have made a positive effort to encourage, and strengthen military ties between China and the U.S.," spokesman Qin Gang told a regular news conference. "But the United States ignored China's serious stance and strong opposition, and is bent on selling weapons to Taiwan, which has contaminated the positive atmosphere for U.S.-China relations." China's vice foreign minister, He Yafei, lodged a strong protest against the deal at the U.S. Embassy last week. China has claimed sovereignty over Taiwan since 1949, when Mao Zedong's Communists won the Chinese civil war and Chiang Kai-shek's Nationalists (KMT) fled to the island. Beijing has vowed in the past to bring Taiwan under its rule, by force if necessary. The United States switched diplomatic recognition from Taipei to Beijing in 1979, recognising "one China", but it remains Taiwan's strongest ally and biggest arms supplier. The Pentagon said the arms sales were consistent with the Taiwan Relations Act, which obliges Washington to help Taipei defend itself.