From the United States to London, the sporting world is increasing security at venues in the aftermath of two bombs exploding near the finish line at Monday's Boston Marathon.
Three people died and more than 170 others were injured in an attack that shattered the traditional Patriots Day celebration in the city. It also sent officials across several sports scrambling to take additional measures to ensure fan safety.
Across the Atlantic Ocean, organizers of the London Marathon said the race will proceed on Sunday despite the threat of terrorism, with British sports minister Hugh Robertson telling the BBC Tuesday that "we won't be cowered by this sort of behavior."
"The best way for us to react is to push ahead with the marathon on Sunday, to get people on the streets and to celebrate it as we always do in London," Robertson told the BBC. "These are balanced judgments but we are absolutely confident here that we can keep the event safe and secure. I think this is one of those incidents where the best way to show solidarity with Boston is to continue and send a very clear message to those responsible."
Prince Harry, the patron of the London Marathon Charitable Trust, is still expected to attend the race and make the presentations to the winners.
"The London Marathon fully expects at this stage ... (to) go ahead as planned on Sunday although we are continuing to review security with the Metropolitan Police in the coming days," Nick Bitel, chief executive of the London Marathon, said Tuesday in an interview on the race website.
With the Boston Bruins' home game on Monday night postponed and the Boston Celtics' scheduled home game Tuesday night canceled, the Boston Red Sox will be the city's first professional team to play following the bombings when they play at the Cleveland Indians on Tuesday night. The Indians announced the flag will be at half-staff and there will be a moment of silence before the game.
"As we welcome the Boston Red Sox tonight to Cleveland for the start of a three-game series, we would like to re-emphasize our commitment to a safe environment here at Progressive Field," the Indians said in a statement. "The safety of our fans, players and staff at Progressive Field has always been, and will continue to be, our highest priority."
The New York Yankees announced they would observe a moment of silence and play "Sweet Caroline" at the end of the third inning of their home game Tuesday night. The song is traditionally played during the eighth inning at Fenway Park in Boston.
In the NHL, the Nashville Predators dispatched bomb-sniffing dogs to Bridgestone Arena before Monday's game against the Canucks, and that will likely remain standard practice for the foreseeable future, according to an SI.com report.
This came on the heels of a team announcement last week that they would wand every 10th person entering Bridgestone Arena as part of a new league-mandated security policy.
Putting fans through metal detectors, wandings, pat-downs and bag searches became part of the routine at major sporting events in the wake of the 9/11, but had gradually diminished at many stadiums. However, it will likely become normal again now that the country's collective guard is back up.
"We have coordinated with all our arenas and they are being secured," NHL deputy commissioner Bill Daly told SI.com in an email, without offering specifics.
Fans in Toronto Monday night endured longer lines as were wanded before entering the Air Canada Centre.
The Pittsburgh Penguins also issued a statement ahead of Wednesday's home game against Montreal.
"We want our fans and employees to know that, following the tragedy in Boston, there will be heightened security measures for upcoming games and events at Consol Energy Center. For obvious reasons, we do not want to identify all of those measures, but we are asking fans to arrive a bit earlier for games and events."
The awareness isn't limited to on-field contests. The National Football League is on high alert for next week's 2013 NFL Draft, and the league said in a statement Tuesday that it will "enhance" its security detail.
"The NFL and its clubs have operated with a very high level of security since 9/11 for all of our games and events," said NFL spokesman Greg Aiello. "For next week's NFL draft, we will review and enhance our already comprehensive security plans with the NYPD, Radio City and our private security partners. We will advise the public more specifically next week prior to the draft."