The FTC last week had asked Amazon and iRobot for more information on the e-commerce giant's buyout offer, which was announced in August.

Warren and the FTC did not immediately respond to Reuters' requests for comment.

According to a recent Politico report, the FTC had started an antitrust review of the deal earlier this month to see if it was illegally boosting the e-commerce company's market share in the connected device market.

(Reporting by Tiyashi Datta in Bengaluru; Editing by Anil D'Silva)