(CNN) Two female plane passengers allege in a federal lawsuit they were sexually assaulted in separate incidents in 2018 on Frontier Airlines flights and that airline personnel failed to report the incidents to police and help them gather evidence.

The suit, filed in Colorado, relates the two women's accounts of apparently unrelated sexual assaults aboard Frontier flights originating in Denver. Each woman says she was assaulted by a male passenger during a flight, one in October and the other the following month. The accused assailants' names are not listed in the suit.

Both women reported the respective incidents to a flight attendant, according to the lawsuit. But the flight attendants, who also are not named, did not report the incidents to anyone else, did not request law enforcement be contacted to meet the plane upon landing, and did not cooperate or assist the complainants with getting evidence or the identities of the assailants or possible witnesses.

The lawsuit asks for class action status and accuses Frontier of failing "to have and/or follow policies and procedures to prevent, report, and respond to sexual assault of its passengers on its flights."

Frontier Airlines corporate communications director Jennifer de la Cruz said they cannot comment on the specific claims in the suit.

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