Persian Gulf carriers are “rushing” to add new flights to the U.S. ahead of possible restrictions in a dispute over whether they are unfairly subsidized, said the chief executives of Delta, American and United airlines.

The additional services emphasize the need for a freeze on the Gulf carriers’ expansion until a resolution of the disagreement is reached, the U.S. airlines said in an April 17 letter to the U.S. government. They also called for full disclosure of the Gulf carriers’ financial statements as well as those of any government-owned entities that may provide goods and services at discounted prices.

The Obama administration is reviewing whether Emirates, Qatar Airways Ltd. and Etihad Airways are receiving unfair support from their governments, making it difficult for U.S. airlines to compete. The public-comment period runs through May, and the Gulf carriers are using that time to expand service, the U.S. airlines said.

“It is now apparent that the Gulf carriers are taking advantage of this delay to change the facts on the ground, rushing to add new wide-body service in an attempt to gain even more market share before the U.S. government acts to counter their subsidized expansion,” American Chief Executive Officer Doug Parker, Delta chief Richard Anderson and United CEO Jeff Smisek said in the letter.

The letter, addressed to the secretaries of State, Commerce and Transportation, is “bolstering our request to freeze capacity given recent announcements by the Gulf carriers to expand since the time we first made our case known to the government,” said Casey Norton, a spokesman for American. Telephone calls to United and Delta weren’t immediately returned.

With assistance from Mary Schlangenstein in Dallas.

To contact the reporter on this story: Michael Sasso in Atlanta at msasso9@bloomberg.net To contact the editors responsible for this story: Edward Dufner at edufner@bloomberg.net Bruce Rule, Molly Schuetz.

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

Photo Credit: A Qatar Airways Boeing 787 Dreamliner lands at Le Bourget airport near Paris. Pascal Rossignol / Reuters