SEATTLE, United States — Amazon.com Inc. may put in a rival bid to acquire Bangalore-based Flipkart Online Services Pvt. even as the Indian e-commerce market leader is in talks with Walmart Inc. for a majority stake sale, according to the Mint newspaper.

Amazon has held early exploratory discussions to buy Flipkart, the newspaper reported citing unidentified people, who said a deal with Walmart is more likely to go through. The world’s biggest retailer is closing in on acquiring 55 percent of Flipkart through a mix of primary and secondary share purchases that could value the Indian company at $21 billion, according to the report.

India is seen as the next big potential prize after the US and China with Kotak Institutional Equities estimating the online market may reach $28 billion by 2020. The e-commerce battle in India has intensified as the burgeoning market lures global giants.

Flipkart and Amazon did not respond to requests for comment by the newspaper, according to the report.

Existing investors in Flipkart such as Tiger Global Management LLC, Accel Partners, Naspers Ltd. and IDG Ventures are among those expected to sell much or all of their shares in India’s biggest online retailer, according to the report.

By Debjit Chakraborty; editors: Pratish Narayanan and Candice Zachariahs.