The US Justice Department is planning to block the proposed merger between American Airlines parent AMR Corp and US Airways Group Inc.

The Justice Department has indicated that it will raise objections to the merger that would have been a significant merger between the two giants. The Justice Department is currently investigating antitrust issues related to the merger.

Meanwhile, a new report by the Government Accountability Office had said that the proposed merger between American Airlines and US Airways is set to reduce the level of competition at a large number of airports in the country. It was found that about 1,665 routes between cities will have one lesser competitor following the merger and affect more than 53 million passengers and a new player will be created in 210 routes impacting 210 routes. The report said that the merger would reduce competition in more number of airports than any merger before.

American and US Air have claimed that the merger would only impact a few number of airports as they overlap on only 12 nonstop routes. The proposed merger would create a leading passenger airline and it comes after significant combinations including the mergers of United and Continental in 2010, Delta Air Lines and Northwest in 2008, and Southwest Airlines with AirTran in 2011.