Washington (AFP) - Was it a sign that Joe Biden is preparing for a bruising election battle ahead?

The US president put a Kansas City Chiefs helmet on his head as he welcomed the Super Bowl winners to the White House on Friday -- then joked he wanted to be back-to-back champions like them.

"Winning back-to-back -- I kind of like that," said Biden, who is aiming for a second term in office in a tough rematch with former president Donald Trump in November's US presidential election. 

Kansas City were the first team to win back-to-back Lombardi Trophies since the New England Patriots in 2003-2004. 

Both Biden and Trump are, meanwhile, aiming to avoid the ignominy of being one-term presidents.

Biden shook hands with Kansas City stars including quarterback Patrick Mahomes and tight end Travis Kelce -- better known to many as US singer Taylor Swift's boyfriend.

Swift herself was not there despite rumors that she might show up to support Kelce. Ahead of the Super Bowl the singer was even the subject of wacky conspiracy theories that their romance was part of a plot to rig the game and get Biden reelected. 

In the end, it was Biden who provided the entertainment for the ceremony on the White House South Lawn.

The 81-year-old Democrat was given a bright red Chiefs helmet and then, to laughter and cheers of "do it" from the NFL stars, proceeded to remove his sunglasses and don the protective headgear.

'Cool'

Biden then walked -- slowly -- to the podium and briefly spoke, though all anyone could hear was "thank you all very much" due to the helmet and the fact that the microphones appeared to be off.

Quarterback Mahomes later demurred when asked if Biden might need the helmet with a tough election battle ahead.

"It was really cool to see him throw that Chiefs helmet on," he told reporters. "We didn't expect that."

There were also more serious undercurrents to the celebration. 

The Kansas City Chiefs' kicker Harrison Butker was in attendance at the White House despite recently attacking Biden's stance on abortion. 

Earlier this month, the 28-year-old three-time Super Bowl champion accused Biden in a commencement speech of being "vocal in his support for the murder of innocent babies."

Butker also faced a backlash for criticizing "dangerous gender ideologies" in a reference to LGBTQ Pride month and taking aim at working women.

He was not among the Chiefs stars who came to talk to reporters in the White House briefing room.

Meanwhile, Biden talked about the need for gun control after a shooting at the team's Super Bowl parade in February left one person dead and 22 wounded.

"As a country, we have to do more to stop the tragic shootings before they happen," Biden said.

He also hailed the team for having "stepped up" to help the community after the shooting.