The top Republican on the Senate Commerce Committee has asked Apple, Amazon and Super Micro Computer for staff briefings about a Bloomberg report that the Chinese government implanted malicious hardware into server motherboards provided by Super Micro.

Senator John Thune said in letters to the chief executives made public on Tuesday that he had sought staff briefings by Oct. 12 from the three companies.

"Allegations that the U.S. hardware supply chain has been purposely tampered with by a foreign power must be taken seriously," Thune wrote.

The companies did not immediately comment on Tuesday on Thune's letter. All have denied the report, published by Bloomberg Businessweek on Thursday.