American Airlines and U.S. Airways will put up a fight against the lawsuit filed by the U.S. Department of Justice and six states seeking to prevent a merger of the two companies.

"We will mount a vigorous defense and pursue all legal options in order to achieve this merger and deliver the benefits of the new American to our customers and communities as soon as possible," says a prepared statement released by AMR Corp., the parent company of American and US Airways Group Inc.

The statement goes on to say that the airlines believe stopping the merger "will deny customers access to a broader airline network that gives them more choices."

The Justice Department and six states—Texas, Arizona, Pennsylvania, Florida, Tennessee,Virginia and Washington D.C.—filed the lawsuit Tuesday in U.S. District Court.

A statement on the Justice Department's website says, "We filed the lawsuit today because we determined that the merger—which would create the world's largest airline and leave just three legacy carriers remaining in the U.S.—would substantially lessen competition for commercial air travel throughout the United States. Importantly, neither airline needs this merger to succeed. We simply cannot approve a merger that would result in U.S. consumers paying higher fares, higher fees and receiving less service."

For the full text of the airlines' statement, go to hub.aa.com/en/nr/pressrelease/american-airlines-and-us-airways-to-fight-justice-department-action. For the Justice Department remarks: www.justice.gov/iso/opa/atr/speeches/2013/at-speech-130813.html