The NHL postponed Monday night's Boston Bruins game at TD Garden because of the Boston Marathon bombings.
No makeup date has been scheduled, and no other games around the country were immediately called off.
Major League Baseball said no changes were planned to ceremonies at ballparks around the country to commemorate Jackie Robinson Day. Spokesman Pat Courtney said several teams informed the league they planned moments of silence.
The NHL said it "wishes to express its sympathy to all affected by the tragic events."
Bruins President Cam Neely, a longtime former Boston player, said the postponement was made in consultation with city, state and league officials. He said authorities are still gathering information and "it is vital they have all resources available for their investigation."
Two bombs exploded near the marathon finish line Monday, killing two people, injuring dozens and sending authorities rushing to aid wounded spectators. A senior U.S. intelligence official said two other explosive devices were found nearby.
Fans arriving early to TD Garden for the Bruins' game against the Ottawa Senators were met by police who were in the area to secure the arena and a nearby federal building.
One officer outside the players' parking lot was telling fans, "The game is canceled. We need you to exit the city safely and quickly."
A minute or two later, Bruins captain Zdeno Chara drove out of the lot, and not long after that the Senators' team bus left down a side ramp.
Police were searching all bags and people entering North Station, which is the train station below the Garden.
An electronic sign that usually lists departure times read "We ask all passengers to be as vigilant as possible and alert authorities if anything suspicious."
The Red Sox game had been over for about an hour when the explosions could be heard at Fenway Park, about a mile from where the bombs went off at the finish line.
Major League Baseball called the bombings a "horrible occurrence" and said the league is monitoring the situation.
"The safety of everyone that comes to our ballparks is always our top priority and we will continue to do everything to ensure a safe environment for our fans," Courtney said.