Some of the Lower Mainland's most vocal sports fans are speaking out against the management of the Vancouver Whitecaps.

The Southsiders are famous for marching to home games at BC Place and singing their support from the stadium's southeast corner, but after a string of losses the group's enthusiasm is waning.

"We demand better," the Southsiders said in an open letter that was posted on Twitter this week. "We intend to hold ownership, management and coaching staff to a higher standard."

Pointing to last Friday's game, which saw the Whitecaps lose 6-0 to Sporting Kansas City, the Southsiders said the club has "reached a critical impasse in its football endeavours."

It was the team’s worst defeat in their MLS history, and the Whitecaps’ third loss in a row. They currently sit in the sixth and final playoff spot in the Western Conference standings with 10 points.

Peter Czimmermann, vice president of the Southsiders, told CTV News the group isn’t calling for anyone’s job, at least not yet. They just want to see management acknowledge a change of strategy is needed.

“We want to make sure that we are heard and there are actions taken by the club,” Czimmermann said. “There has been some complacency … We want to aspire to win things, we want to aspire to be better.”

The Southsiders did not put any of the blame on the players, however, who they continue to back wholeheartedly.

"We are fierce in our support for the players on the pitch," their letter said. "The players are in just as tough of a position as we are and they need our voices now more than ever."

To signal their displeasure, the Southsiders said they will be marching to Friday's game against Real Salt Lake later than usual – just in time for kickoff – and they won't be using drums during their chants.

They also said they will be singing an amended song sheet "with more four-letter words."

Czimmermann said he’s not sure whether the Southsiders will escalate their protest if the team doesn’t win their next game Friday night, but with at least 2,000 “scarf-carrying members,” he believes they have the numbers to force some kind of change within the organization.

“We are organized and we want to hold the management accountable,” he said.

With files from CTV Vancouver’s Christina Heydanus and The Canadian Press