E-commerce companies in the country are estimated to have clocked sales worth USD 1.5 billion (Rs 11,085 crore) in less than three days of festive sale with both Flipkart and Amazon India claiming to be leading the tally. According to RedSeer Consulting, e-commerce companies in India have achieved USD 1.5 billion in the first 2.5 days of the festive sale -- led by sale of 4.6 million units of smartphones (translating into USD 800 million), large appliances (USD 170 million) and fashion (USD 120 million).It added that the industry is on track to reach the USD 3 billion-mark -- twice that of last year -- by the end of the five-day festive period. Players like Flipkart, Amazon India, Paytm and ShopClues have lined up attractive offers and discounts across categories to woo customers to shop on their platforms.And like previous years, Flipkart and Amazon India continue to claim bigger numbers than the others.In the smartphone category, Flipkart said it sold over three million units in a day -- a new record by the Walmart-backed company that started sale in the smartphone category on the second day of its 'Big Billion Days' sale.Amazon, on the other hand, contended that brands like Apple, OnePlus Samsung and Xiaomi continue to see blockbuster sales on Day 2 and "Indian customers continue to see us as their preferred destination to buy smartphones (and more) across all price points".On TVs, Amazon India said it has sold "as many TVs in a single day as all of India usually buys in a day to see a nearly 3.5X spike year-on-year", while Flipkart claimed that "1 in 4 TVs worldwide was bought on Flipkart, creating retail history on a never-before-seen scale in India".Despite having invested millions of dollars on ramping up infrastructure and logistics, both companies have kept mum about their business targets during the festive season.Flipkart CEO Kalyan Krishnamurthy had indicated that the company is on a strong growth trajectory and could possibly achieve all its numbers "by the fourth day itself" as it is a "clear leader in smartphones, fashion and home products".He also exuded confidence that Flipkart would not lose out to competition as it understands requirements of Indian customers better.Snapdeal, which was last year in talks for a buyout by Flipkart, said its 'Mega Diwali Sale' is sharply focused on products that are traditionally a part of annual Diwali shopping by families across the country."In the first 36 hours of the sale, the shipped volumes have more than doubled and the trend continues to grow rapidly," Snapdeal said adding that consumers shopped across categories like electronics, home decor and fashion.