Separately, American said it is ending code-share agreements with both Qatar Airways and Abu Dhabi's Etihad Airways amid a trade dispute with the two Middle Eastern carriers.
American, the largest U.S. carrier, in a filing with the Securities and Exchange Commission said that Qatar Airways, which last month expressed interest in buying up to 10 percent of American, had withdrawn its previous antitrust filing with the Federal Trade Commission and submitted a new filing on Monday.
Representatives for Qatar Airways could not be reached for comment. The chief executive of Qatar Airways, Akbar al-Baker, said last week that the carrier would push on to buy shares on the open market despite American's opposition.
The FTC did not comment. The agency typically does not disclose details of requests for antitrust approval filed by companies seeking to acquire stakes in rivals.
American Airlines' own rules require advance approval from its board for the purchase of a stake of 4.75 percent or more. The airline last month also noted that "there are foreign ownership laws that limit the total percentage of foreign voting interest to 24.9 percent."
"ILLEGAL SUBSIDIES"
American's decision to cancel code-share agreements, which allow airlines to book passengers on each other's flights, ramps up an acrimonious dispute between U.S. carriers and Gulf competitors.
American and other U.S. carriers have charged that Qatar Airways, Etihad and Emirates Airline[EMIRA.UL] get an unfair competitive edge from state subsidies that allow them to offer lower fares and more amenities to long-haul, international travellers.
The U.S. carriers are pressing the United States government to curb the Middle Eastern carriers' access to U.S. airports, and the White House is considering their request, according to government officials and airline executives who have spoken to the White House. The Middle Eastern carriers have rejected the complaints about subsidies.
The decision to cancel code-sharing deals with the two carriers would not have a material financial impact on American, the carrier said, and "is an extension of our stance against the illegal subsidies that these carriers receive from their governments."
Etihad Airways is a flag carrier and the second-largest airline of the United Arab Emirates (UAE), based in Abu Dhabi. Qatar Airways is the state-owned flag carrier of Qatar.