San Francisco, Sep 12 (DPA) The US Department of Justice is looking into the advertising and search alliance between Microsoft and Yahoo, the companies said Friday.

Yahoo and Microsoft, which trail a distant second and third respectively to Google in the internet search market, announced their deal in late July in a bid to combine forces and challenge the web giant.

Under the arrangement, Microsoft will provide search and related advertising tools on Yahoo's pages, in return for a 12-percent revenue cut during the first five years of the deal. Yahoo estimates the pact will add $500 million to annual operating income

while cutting capital expenses by $200 million.

While the antitrust probe had been expected, analysts say that the Department of Justice is unlikely to block the deal since the two companies' combined share of the market would still be less than half held by Google.