DENVER (Reuters) - An Oregon man suspected of raping a woman inside a concourse at Denver International Airport was formally charged on Tuesday with sexual assault, prosecutors said.

Noel Alexander Bertrand, 26, is facing one count of class 3 felony sexual assault for the April 12 incident, said Lynn Kimbrough, spokeswoman for the Denver District Attorney's Office.

"Under the Colorado statute, third-degree sexual assault carries a potential life sentence," Kimbrough said.

Bertrand was arrested last week after a 22-year-old woman told police she was attacked by Bertrand about 12:30 a.m. inside the airport's "A" concourse.

The unidentified woman said she shared drinks with Bertrand at an airport bar and he assaulted her after she rejected his sexual advances.

Two Frontier Airlines mechanics who witnessed the alleged assault intervened and along with security personnel held Bertrand until Denver police arrived to arrest him.

Bertrand remains in custody on a $50,000 bond and will be advised of the charges against him at a court hearing later this week.

According to Leatherneck Magazine, a publication for U.S. Marines, Bertrand served as a U.S. embassy guard in Qatar, Venezuela and Ireland before leaving the corps.

(Reporting by Keith Coffman; Editing by Dan Whitcomb and Greg McCune)