Buzz on Internet: 'Sending prayers out for Boston'

American sportstars react with horror to the Boston Marathon bomb blasts.

Two explosions rocked the Boston Marathon on Monday, killing at least three people and injuring over 140, as runners crossed the finish line on a day when tens of thousands of people pack the city's streets to watch one of the world's best-known marathons.

The police also did not specify whether the two blasts were an act of terror. But the celebrities poured their heart out on Twitter.

World and Olympic Champion Usain Bolt tweeted, "What a sad news #bostonmarathon. The sprinter added, "Praying for all."

The former undisputed heavyweight champion boxer Mike Tyson also sympathised and said on his Twitter account, "Praying for everyone at the Boston Marathon."

Retired American former World No 1 professional tennis player Andy Roddick tweeted, "I hate hearing stories like the Boston marathon. So senseless."

The National Basketball Association's Celtics were to host the Indiana Pacers at TD Garden on Tuesday but the game had been cancelled and would not be rescheduled, the league said.

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

Boston Celtics tweeted, "The Celtics family sends its thoughts and prayers to the friends and families affected by today's tragedy in Boston. Stay safe."

Other horrified NBA players also tweeted their reactions.

The Los Angeles Lakers shooting guard Kobe Bryant tweeted, "#unity #peace #love #prayer"

Miami Heat's LeBron James said, "Prayers goes out to those involved/hurt in #Boston Marathon. WTF is wrong with people man. Just sad."

Boston Celtics's point guard Rajon Rondo tweeted, "Sending prayers out for Boston."

Los Angeles Lakers's Pau Gasol also expressed sympathies on his Twitter account, "Shocked and sad to hear about the explosions at the Boston Marathon today. There are things that I will never understand. #PrayForBoston"

English professional golfer Ian Poulter tweeted, "Sickening news in Boston, really sad, our thoughts are with all the family's & friends affected."

American professional beach volleyball player Kerri Walsh Jennings said, "So many prayers going out to Boston and the people impacted by the explosions. Prayers that the people behind it get caught & put away."

The undefeated American professional boxer Floyd Mayweather, wrote "My thoughts and prayers are with those hurt from the tragedy at the Boston Marathon. Much love to the city of Boston, stay strong."

American socialite and reality television star Kim Kardashian tweeted, "My heart is breaking for everyone effected or injured in the explosion at the Boston Marathon. God bless you all! My prayers are with you!"

Actor and director Ben Affleck expressed his sorrow by saying, "Such a senseless and tragic day. My family and I send our love to our beloved and resilient Boston. Praying for everyone at #Boston Marathon right now. Sometimes I can't even believe these things happen in the world everyday, so sad."