Walmart Inc’s Flipkart and Amazon.com Inc have filed legal challenges against the resumption of an antitrust investigation into their business practices, according to sources and a legal filing viewed by Reuters.

An Indian trader body has raised objections to Walmart Inc’s (WMT.N) $16 billion acquisition of e-commerce firm Flipkart, though lawyers and sources said the complaint to the country’s antitrust regulator is unlikely to threaten the deal.

Hogan Lovells and Shardul Amarchand Mangaldas have advised U.S. retailer Walmart on its agreement to pay $16 billion for a roughly 77 percent stake in Indian e-commerce firm Flipkart, which turned to Khaitan & Co. for advice.