Police said the incident happened at 11 p.m. PT in the area of 3rd Avenue and Dominion Street, as two officers were dealing with three pedestrians.
The officers discovered one of the pedestrians had a warrant out for his arrest, according to a statement from RCMP.
"While members were taking the male into custody he sustained what appears to be self-inflicted injuries to his neck," the statement said.
"An officer was also stabbed. Both were transported to hospital for medical care. A knife was seized as evidence."
The officer has been treated in hospital and released. Police did not reveal the condition of the man RCMP arrested, referring calls to the Independent Investigations Office.
The IIO has yet to decide whether the incident falls within its jurisdiction.