Delta Air Lines has asked U.S. regulators to prevent American Airlines from starting flights between Los Angeles and Mexico City, the latest shot in recent friction between the two carriers.

American has sought clearance to take over the route from Alaska Airlines, which has agreed to turn it over before June. The Department of Transportation should deny American’s request and have an open competition for the route instead, Delta said in a filing. Under a U.S.-Mexico treaty, Alaska and United Airlines are the only U.S. carriers that are allowed to fly between the two cities.

“Delta is a strong and growing challenger at Los Angeles and to Mexico, but needs important limited entry authority on this route to compete,” Delta said.

The skirmish is part of a competition between Delta and American to grow at Los Angeles International Airport, where no airline enjoys a dominant market position. On March 27, U.S. regulators rebuffed American’s bid to start serving Tokyo’s Haneda airport from Los Angeles using a route authority to be taken from Delta.

Alaska and American, in a written response to the Transportation Department, called Delta’s filing a “spurious effort to obstruct and delay.”

Jenna Arnold, an American spokeswoman, said Thursday that the route request “is an example of American’s strong relationship with Alaska Airlines and underscores its commitment to providing customers a world-class global network from LAX.” She declined to comment further.

Delta didn’t responded immediately to a request for comment Thursday.

To contact the reporters on this story: Michael Sasso in Atlanta at msasso9@bloomberg.net; Mary Schlangenstein in Dallas at maryc.s@bloomberg.net To contact the editors responsible for this story: Edward Dufner at edufner@bloomberg.net Bruce Rule

This article was written by Michael Sasso and MARY SCHLANGENSTEIN from Bloomberg and was legally licensed through the NewsCred publisher network.

Photo Credit: Delta and American are getting increasingly confrontation as Delta is trying to block American from starting flights from LAX to Mexico. In this Nov. 11, 2013 file photo, airport employees preparing to clear security as they wait to reopen after a shooting at Terminal 3 caused a shutdown of Los Angeles International Airport. Reed Saxon / Associated Press