Beijing lashes out at any diplomatic action that might lend Taiwan legitimacy, and has responded with growing anger to visits by Western officials and politicians.
Taiwan's armed forces are well-equipped but dwarfed by China's. Tsai has been overseeing a modernisation programme and has made increasing defence spending a priority.
The foreign ministry in Beijing on Monday condemned the alleged hack, saying it "seriously endangers China's national security and users' personal data security".
The United States will continue to support a peaceful resolution of cross-Strait issues, consistent with the wishes and best interests of the people on Taiwan.
