Mounties are investigating reports that a man sexually assaulted a sleeping passenger on an Air Canada flight this week.

The plane was heading from Toronto to Vancouver in the early morning hours Wednesday when the alleged attack took place, according to Richmond RCMP.

“The alleged suspect, a 39-year-old Pakistani national, was observed inappropriately touching a female passenger as she slept,” Cpl. Dennis Hwang said in an email statement.

No other details about the allegations have been released by police, but a witness told CTV News she overheard crew members trying to comfort the woman after the incident.

A flight attendant told her “I’m so sorry this happened,” the witness said.

After the flight landed, officers boarded the plane, escorted the suspect off the aircraft and took him into custody. Richmond Mounties said they are continuing to investigate with assistance from Air Canada and Vancouver International Airport.

Air Canada would not comment on the incident Thursday other than to say a passenger “became unruly” on flight AC151, and that the matter is being dealt with by the RCMP.

Women Against Violence Against Women, a rape crisis centre in Vancouver, told CTV News it’s airlines' duty to ensure the safety of the people on board their aircraft.

“Airlines are responsible for preventing sexualized violence on their flights and for creating safety for all their passengers,” sex assault counsellor Jordan Pickell said.

When assaults do take place, “it’s up to the airlines to support people who are impacted and to hold perpetrators accountable,” she added.

A spokesperson for Air Canada would not provide details on the company’s policy for dealing with such situations when asked Thursday.

With a report from CTV Vancouver’s Rena Heer