A US airline apologized yesterday to nine Muslim American passengers from the Washington area who were removed from a flight out of Reagan National Airport, but a Muslim civil rights group said it intends to press a discrimination complaint against the airline for its treatment of the passengers. "It is incumbent on any airline to ensure that members of the traveling public are not singled out or mistreated based on their perceived race, religion or national origin. We believe this disturbing incident would never have occurred had the Muslim passengers removed from the plane not been perceived by other travelers and airline personnel as members of the Islamic faith," said the complaint filed with the US Department of Transportation by the Washington-based Council on American-Islamic Relations (CAIR), an advocacy group. The New Year's Day incident aboard an AirTran flight to Orlando marked the latest case in which Muslim or South Asian travelers have alleged that they were illegally singled out for scrutiny. Contradictory accounts given by airline and federal aviation security authorities also highlight the difficulty of decision-making and affixing responsibility in tense situations involving a perceived threat. Laila Al-Qatami, a spokeswoman for the American-Arab Anti-Discrimination Committee, said her group tracked about 20 such reports in 2008, although the AirTran case was unusual because the airline initially refused to rebook the passengers. "It seems in this case the airline has to take another look at what its policies are, how it handles a situation like this and what it considers suspicious behavior," Al-Qatami said. In 2008, the Transportation Department said it handled 87 complaints alleging discrimination by airlines based on race, ethnicity, national origin or color, but only four were security related, spokesman Bill Adams said. However, Adams said security checkpoints staffed by the Transportation Security Administration are outside the department's jurisdiction. TSA spokesman Christopher White said the agency's office of civil rights has received 32 complaints since Oct. 1. AirTran initially defended its actions in removing the nine passengers after others reported their remarks about the safest place to sit on an airplane. But as reports of the incident spread yesterday, the airline said in a statement that it had offered the group a refund for their replacement tickets and free return airfare. It also apologized to 95 other passengers whose flight was delayed about two hours. "We regret that the issue escalated to the heightened security level it did on New Year's Day, but we trust everyone understands that the security and the safety of our passengers is paramount and cannot be compromised," AirTran spokesman Tad Hutcheson said. "Nobody on Flight 175 reached their destination on time . . . and we regret it." Brothers Kashif Irfan, 34, an anesthesiologist, and Atif Irfan, 29, a lawyer, both Alexandria residents, said they believed that their families and a friend were profiled at least in part because of their appearance. All but one of their group are native-born U.S. citizens, and the ninth is a legal permanent U.S. resident, they said; six are of Pakistani descent, two are of Turkish descent, and one is African American. All five adults and a teenager appeared traditionally Muslim, with the men wearing beards and the women in head scarves, they said. They were on their way to a religious retreat in Orlando. The incident began about 1 p.m. Thursday when Atif Irfan, his wife, Sobia Ijaz, 21, and Kashif Irfan's wife, Inayet Sahin, 33, took their seats at the rear of the plane. Officials said two teenage girls sitting nearby became alarmed when they heard Sahin remark that sitting near the engines would not be safe in the event of an accident or an explosion. The girls told their parents, who told a flight attendant, AirTran officials said. The Muslim passengers said their innocuous banter was misconstrued. "The conversation we were having was the conversation anyone would have," Atif Irfan said in a telephone interview from Florida. "She did not use the word 'bomb,' she did not use the word 'explosion.' She said it would not be safe to sit next to the engines in the event of an accident." Officials with the airline and the TSA differ over what happened next. AirTran officials said the flight attendant notified two federal air marshals on board about the report before telling the captain. The air marshals called both the FBI and airport police to the scene before the pilot emerged from the cockpit, the airline said. But TSA officials said the pilot, who has authority over who flies on his plane, requested that the air marshals investigate and that the passengers be removed. FBI agents quickly cleared the passengers of wrongdoing. However, an AirTran gate agent barred them from booking a new flight because she had not been notified of their clearance, the airline said.