The National Association of Realtors has requested that the Federal Trade Commission block the merger of rival internet housing search giants Zillow and Trulia, the New York Post is reporting.

The $3.5 billion deal, announced earlier this month, would leave the merged companies in control of more than two-thirds of all internet home searches.  Realtor.com, the Realtor-affiliated site which is operated by for-profit Move, Inc., is a distant third.

Few Wall Street analysts have predicted that the FTC will block the deal, since thousands of different sites on the internet display real estate listings. The FTC has until Sept. 3 to request additional information on the proposed merger, which would delay the merger. The deal had been expected to close next year.

For additional coverage of the Zillow-Trulia deal and its impact on the real estate industry, see here.