A Shuttle America flight attendant 'will no longer serve United customers' following an investigation into a Muslim chaplain's complaint of discriminatory treatment during a flight, an airline spokesman said Wednesday.

In an email to The Associated Press, United spokesman Charles Hobart said the airline 'does not tolerate behavior that is discriminatory — or that appears to be discriminatory — against our customers or employees.'

The statement came five days after Northwestern University chaplain Tahera Ahmad said a flight attendant declined her request for an unopened can of Diet Coke because it could be used as a weapon. The flight was operated by Shuttle America for United.

Ahmad's description of the incident on her Facebook page Friday May 29 led to news articles and a Twitter campaign supporting her.

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Speaking out: Tahera Ahmad (seen left and right) has said a flight attendant last week declined her request for an unopened can of Diet Coke because it could be used as a weapon

She wrote on the social media site that during a flight Friday from Chicago to Washington, D.C., ' The flight attendant asked me what I would like to drink and I requested a can of diet coke.

'She brought me a can that was open so I requested an unopened can due to hygienic reasons.

'She said no one has consumed from the drink, but I requested an unopened can.

'She responded, "Well I'm sorry I just can't give you an unopened can so no diet coke for you."'

Ahmad wrote that the flight attendant gave another passenger an unopened beer can but told her that people weren't allowed to have unopened cans because they could be used as weapons.

'She said, "You would use it as a weapon." At that point I felt she crossed a line,' Ahmad told the AP. She asked other passengers if they saw what happened, and one man swore at her, Ahmad said.

On Facebook, Ahmad wrote ' ...I told her that she was clearly discriminating against me because she gave the man next to me an unopened can of beer.

'She looked at his can, quickly grabbed it and opened it and said, "it's so you don't use it as a weapon."

Incident: Ahmad has said she asked other passengers if they saw what happened, and one man swore at her

Her side: Ahmad posted this message to Facebook after United had described the incident as 'a misunderstanding regarding a can of diet soda'

' Apphauled at her behavior I asked people around me if they witnessed this discriminatory and disgusting behavior and the man sitting in an aisle across from me yelled out to me, "you Moslem, you need to shut the F*** up."

'I said, "what?!"

'He then leaned over from his seat, looked me straight in the eyes and said, "yes you know you would use it as a WEAPON so shut the f*** up."'

She was wearing the Muslim headscarf known as the hijab.

United previously issued a statement that described the incident as 'a misunderstanding regarding a can of diet soda.'

'I am truly dissapointed at the latest statement by United Airlines,' Ahmad said in a Facebook post May 31. 'Unfortunately United has dismissed my entire narrative and trivialized it to a can of soda.'

The airline sharpened its stance as Ahmad and the Chicago chapter of the Council on American-Islamic Relations prepared Wednesday for a news conference in Chicago.

Video courtesy Noor Wazwaz

The new United statement also followed a letter from Northwestern University President Morton Schapiro to United CEO Jeff Smisek requesting a formal apology and 'assurances that United will train its staff so that she and others are never again subjected to such discrimination on a United flight.'

Hobart said Wednesday that United's 'customer-facing employees undergo annual and recurrent customer service training, which includes lessons in cultural awareness.' He said United will 'continue to work with all of our partners' on cultural awareness.

'While United did not operate the flight, Ms. Ahmad was our customer and we apologize to her for what occurred on the flight,' Hobart said.