NEW DELHI, Aug 30 (Reuters) - Amazon.com Inc (AMZN.O) has asked India"s market regulator to order withdrawal of conditional approval given to its warring partner Future Group"s $3.4 billion retail assets sale, citing a court ruling in the U.S. company"s favour, a letter seen by Reuters showed. Amazon has for months been locked in a dispute with Future, accusing India"s second-largest retailer of violating some pre-existing contracts by selling its retail assets to market leader Reliance Industries (RELI.NS) last year. Future denies any wrongdoing. The Supreme Court this month dealt a blow to Future when it said an interim decision by a Singapore arbitrator in October 2020 was valid and enforceable in India. Amazon had filed the complaint leading to the arbitration ruling, which put Future"s deal with Reliance on hold. In a letter to the Securities and Exchange Board of India (SEBI) on Aug. 17, seen by Reuters, the U.S. company wrote: "Amazon requests you to take all such action as is necessary to comply with the Supreme Court Judgment." The letter added that the approval from stock exchanges "were conditional on the outcome of the ongoing proceedings," urging SEBI to order their withdrawal. SEBI and the Indian stock exchanges did not immediately respond to a request for comment outside regular business hours. Amazon declined to comment. Future and Reliance did not respond to requests for comment. The letter marks the latest twist in the bitter legal spat involving two of the world"s richest men, Amazon founder Jeff Bezos and Reliance Chairman and Managing Director Mukesh Ambani. The eventual outcome is seen reshaping India"s pandemic-hit shopping sector and deciding whether Amazon can blunt Reliance"s dominance of the country"s nearly trillion-dollar retail market. The dispute is far from over, though. Future Retail (FRTL.NS) on Saturday filed a new case against Amazon at the Supreme Court, seeking to secure approval of the deal whose failure it says will cause thousands of job losses and put bank loans at risk, Reuters reported. read more In its latest case filing, the Indian retailer is asking the Supreme Court to hear its challenge afresh. Separately, the Singapore arbitration panel continues to hear the dispute.