WASHINGTON, Oct 3 (Reuters) - Two U.S. senators said they were investigating short video sharing app TikTok's reported decision recently to hire several high-level executives from its Chinese parent company, ByteDance. Senators Richard Blumenthal, a Democrat, and Republican Marsha Blackburn said in a letter on Tuesday to TikTok CEO Shou Zi Chew that the personnel moves further call "into question the independence of TikTok's operations and the security of its U.S. users' information." TikTok, which did not immediately respond to a request for comment, is used by more than 150 million Americans and has faced calls from U.S. lawmakers for...