SAN JOSE -- A dispute between the Earthquakes and their most ardent supporters has escalated after management revoked the 1906 Ultras' rights to display banners at home games.

In response, the fans who sit behind the north goal at Buck Shaw Stadium were silent Saturday night throughout San Jose's 2-0 victory over Chivas USA. The Ultras usually sing, chant and pound drums for all 90 minutes of home games.

They vow to remain silent until the team lifts the sanctions, including one issued Friday that indefinitely revoked the Ultras' rights to display homemade banners, known as tifa.

The latest conflict between the Major League Soccer team and the 200-strong Ultras comes a year before the Earthquakes plan to open a new stadium. At a time the team is trying to build a strong fan base to help fill the new 18,000-seat stadium, management is struggling with a minority of passionate supporters who bring a European flavor to games that's not seen in other U.S. sports leagues.

As MLS officials promote a family friendly environment, they have tried to keep a leash on supporters groups to prevent the seeds of hooliganism from sprouting. Most soccer teams have special supporter sections in their stands.

Although independent, the Ultras have an arrangement with the Quakes to sit together, unfurl banners and sing and chant.

"It's the unique part of our culture of soccer," Quakes president Dave Kaval said Monday. "It's a differentiator."

Aside from some lewd chants, questionable banners and drunkenness, the Quakes have had few problems with their fans in the five-plus seasons since they have re-entered MLS.

The current issue has been building since the Ultras were placed on indefinite probation in April after a melee in Portland in which police reported a group of about a dozen men, many wearing Earthquakes scarves to cover their faces, jumped on the hood and smashed the windshield of the car of a Timbers fan on the way to the game at Jeld Wen Field. The driver also told police someone opened his door and punched him.

A Portland detective interviewed fans in the Bay Area, according to Ultras member Mel Marcia of Hayward. He added that the fan group considers the incident over because authorities have the names of those who allegedly were involved.

"There were some transgressions in Portland, but ... the people who were involved stepped up and took the blame," Marcia said.

Portland police spokesman Pete Simpson said Monday that the case is ongoing.

Because of the incident, Quakes management has closely monitored the Ultras' actions. Team officials disapproved of a banner unfurled at Buck Shaw two weeks ago in a game against the Timbers. The banner read, "Only in PDX, running over a female makes you a victim." It was in reference to claims that fans attacked the car in April only after a female Quakes fan was grabbed by the driver and then fell out of the vehicle.

"We don't want to be part of violence in any way," Kaval said. "It has no place in soccer. It threatens the very viability of our product and sport in North America."

The Ultras' biggest issue is a ban from traveling as a supporters group to an Aug. 31 game against the Galaxy at the Home Depot Center.

Marcia said some Ultras are considering asking for refunds for season tickets to the new stadium.