The Boston Celtics regular season-ending home game on Tuesday against Indiana has been cancelled after deadly explosions rocked the Boston Marathon, the NBA announced Monday.

The game, which was set to be played at the downtown Garden arena just blocks from the site of the blasts, would not be re-scheduled, the league said.

The move follows the National Hockey League's decision to postpone Monday night's contest between the Boston Bruins and the Ottawa Senators.

"The NBA expresses its sympathy to all those affected by the tragedy in Boston earlier today," the NBA said in a news release.

Miami Heat star LeBron James tweeted Monday that he was thinking about those affected by the blasts.

"Prayers goes out to those involved/hurt in #BostonMarathon," tweeted James.

NHL officials said unlike the Celtics' contest, the Bruins' home game would be rescheduled at a later date.

"The National Hockey League wishes to express its sympathy to all affected by the tragic events that took place in Boston earlier this afternoon," the league said.

The Boston Red Sox's home game against the Tampa Bay Rays on Monday morning wasn't affected. The Red Sox had beaten the Rays 3-2 before the twin blasts caused chaos in the city, killing at least three and injuring scores of others.

"Very sad to hear the news coming out of Boston," Red Sox outfielder Shane Victorino said on Twitter after the team had travelled to Cleveland. "Horrific. My thoughts and prayers to all those involved."