The U.S. men's soccer team on Sunday sent an open letter to members of Congress urging them to pass stricter gun laws following a surge in mass shootings while NBA players and coaches also raised the issue ahead of Game Two of the Finals.

A shooting in Philadelphia left at least three people dead and 11 others wounded, police said on Sunday in the latest case of gun violence in the United States after recent massacres in Texas, New York and Oklahoma where dozens died.

"Our ability to affect change is limited, but yours is not," the U.S. men's team said in the letter.

"You could vote this week to address gun violence in America, and in fact, you will be given that opportunity. In the coming days, the U.S. House of Representatives is voting on several bills that would address this serious issue. Please vote yes on all the bills being considered."

Like scores of other teams across the United States this weekend, the squad wore orange arm bands during their friendly on Sunday in support of "Wear Orange Weekend," an annual event calling for an end to gun violence.

Ahead of Game Two of the NBA Finals, players and coaches wore orange t-shirts that said "End Gun Violence" on the front and a list of organizations working to address the issue on the back.

"We feel very strongly as a league that it is time for people to take notice and take part in what should be a nationwide effort to limit gun violence that out there," Warriors head coach Steve Kerr said.

"And there are ways to limit it. There are proven laws that are waiting to be passed."

There have been at least 239 mass shootings in the United States so far this year, according to the Gun Violence Archive, a nonprofit research group. It defines a mass shooting as one in which at least four people are shot, excluding the shooter.

U.S. President Joe Biden on Thursday called on Congress to ban assault weapons, expand background checks and implement other gun control measures to address the string of mass shootings.

A broad majority of American voters, both Republicans and Democrats, favor stronger gun control laws, but Republicans in Congress and some moderate Democrats have blocked such legislation for years.