NEW DELHI, June 28 (Reuters) - Facebook Inc (FB.O)-owned WhatsApp messenger said on Monday it was appointing a former Amazon (AMZN.O) executive as the head of payments in India as it looks to scale the service in its biggest market by users. Manesh Mahatme, officially director WhatsApp payments - India, will help improve users" payments experience and grow the business, WhatsApp said in a statement, confirming a Reuters newsbreak in March. read more Mahatme was previously a senior executive at Amazon where he led the product and engineering teams for U.S. online retailer"s payments business, Amazon Pay, in India. He also worked earlier with Citigroup (C.N) and Indian mobile carrier Bharti Airtel (BRTI.NS). WhatsApp, which has more than 500 million Indian users, last year received a much-delayed approval for the launch of its payments system in the country, but so far its rollout has been capped by regulators at 20 million users. But it has big ambitions and a deal by Facebook last year to invest $5.7 billion in billionaire Mukesh Ambani"s Jio Platforms digital unit will allow WhatsApp to offer payments services to millions of mom-and-pop stores. WhatsApp also has plans to expand its partnership with banks in a bid to offer financial services such as pensions and insurance, its India head Abhijit Bose - also a payments industry veteran - said last year.