The RCMP's hate crime unit is investigating after racist graffiti was sprayed on the side of a Vancouver-area mosque.

A racial slur that targets Arabs was etched in large black letters onto the Islamic Cultural Centre in Port Coquitlam, east of Vancouver. The culprit would have had to scale a fence to have access to the building.

Omarr Khan drove by the scrawl and stopped his car immediately.

"I got on the phone to call the police but couldn't find the number for 911 non-emergency number. So by that time, this guy came and I just said, ‘let's just get it off,'" Khan said. He grabbed a watering hose from the side of the building and used it to spray the offensive words off the wall.

RCMP say they are treating the incident very seriously, and are appealing for witnesses to come forward.

Robert Newton, who prays at the mosque, says worshippers have used the building since 1994 without a problem.

"I was saddened but I believe it's an isolated incident, certainly not characteristic of our community," he said.