Aug 28 (Reuters) - Tesla Inc (TSLA.O) Chief Executive Elon Musk has signaled competition concerns over Nvidia Corp"s (NVDA.O) planned purchase of British chip designer Arm, the Telegraph reported on Saturday, citing multiple sources. E-commerce giant Amazon.com Inc (AMZN.O) and smartphone maker Samsung Electronics Co Ltd (005930.KS) have also lodged opposition to the deal with U.S. authorities, the newspaper reported. Earlier this year, the U.S. Federal Trade Commission opened an in-depth probe into the takeover. read more The probe findings are expected in the coming weeks, according to the newspaper. Tesla, Amazon, Samsung and Nvidia did not immediately respond to a Reuters request for comment. Nvidia is likely to seek European Union antitrust approval for the $54 billion purchase of Arm early next month, with regulators expected to launch a full-scale investigation after a preliminary review, people familiar with the matter have said. read more