SAN JOSE -- San Jose's mayor has apologized for the behavior of Sharks fans who loudly booed the Canadian national anthem before Game 5 of a second-round playoff series against the Edmonton Oilers.

"This showed a lack of respect to our Canadian neighbors, to the players of both teams, and to our own residents," Mayor Ron Gonzales said in a statement.

"I sincerely hope that this occurrence of bad behavior by a small number of fans is an aberration caused by misplaced enthusiasm and an ignorance of the expected courtesy that we should extend to all teams and players in every stadium, ballpark and arena."

The vociferous booing Sunday night started from the opening notes of singer Annmarie Martin's rendition of "O Canada." While other fans attempted to drown it out by singing along, the boos were audible until the final notes.

Sharks officials thought their crowd was responding to a handful of Canadian fans that apparently booed a picture of Sharks star Joe Thornton on the video board at the start of the American anthem last Friday night before Game 4. The microphone on the Bay Area broadcast picked up some of the booing.

Edmonton Mayor Stephen Mandel said he agreed with Gonzales that there was never an excuse for fans to boo a national anthem. Game 6 of the series is Wednesday night in Edmonton.

"I'm sure Edmonton's fans will show their true colors on Wednesday and we'll celebrate in a manner in which all of Edmonton, and all of Canada can be proud," Mandel said.

The Sharks had 10 Canadians in uniform Sunday night.

"We have a lot of Canadians on our team, so that was a little disrespectful," forward Scott Thornton said.

Pregame anthem booing was a hot-button issue in sports shortly after the beginning of the war in Iraq, with fans in Chicago's Wrigley Field, Montreal's Bell Centre and other arenas booing their neighbors' anthem from 2002-04.