Google's intention to acquire ITA Software is drawing increased scrutiny from the US Department of Justice, which is seeking more information from the parties as it tries to determine if the deal raises antitrust concerns.

"While this means we won't be closing the deal right away, we're confident that the DOJ will conclude that online travel will remain competitive after this acquisition closes," wrote Andrew Silverman, a Google senior product manager, in an official blog post on Friday afternoon.

Google received the formal "second request" for information from the DOJ last week regarding the company's agreement to buy ITA, a maker of air-travel flight-information software, for US$700 million in cash.

ITA counts major airlines and online travel agencies among its customers, including American Airlines, Continental Airlines, Kayak, Orbitz, Southwest Airlines, TripAdvisor, United Airlines, US Airways, Virgin Atlantic Airways and Microsoft's Bing.

At the time, some industry observers commented that government regulators might object to the deal because ITA's products are key components in the systems of many online travel agencies and airlines.

A DOJ spokeswoman declined to comment on Monday. The agency's review process for mergers and acquisitions calls for an initial "waiting period" review that lasts between 15 and 30 days, according to information on the DOJ's Web site. During this first phase, DOJ staffers can request that the companies involved provide information voluntarily and can engage in discussions with them. At the conclusion of this first phase, the DOJ decides whether to give the deal the green light or look into it further during a "second request" stage.

ITA, based in Cambridge, Massachusetts, and founded in 1996, and Google announced the acquisition agreement on July 1 of this year.

At the time, Google said it's interested in ITA Software's technology and products because they will improve the ability of Google search engines to deliver flight information to travelers and users in general.

A significant portion of Google queries are travel related, and there is a big opportunity to innovate upon and improve on existing search services, according to the company.

"Airline travel and [online] search are a perfect opportunity for more innovation, more investment," as well as for more competition, Google CEO Eric Schmidt said at the time.

ITA Software is privately held and has about 500 employees.