NEW DELHI (Reuters) -India's financial crime agency has privately sought sales data and other documents from smartphone players including Apple and Xiaomi as part of an investigation into Amazon and Walmart-owned Flipkart, sources familiar with the matter told Reuters.

The agency's queries come in the backdrop of India and the United States nearing a trade deal. The protectionist e-commerce regulations in India have been part of those discussions, according to one Indian official, as U.S. authorities have long called for opening up the sector.