The school shooting tragedy in Connecticut that took place on Friday was a sad and horrific event that shook American and the sports world.

Many different athletes went onto Twitter to express their grief and sadness at the event, while the NFL asked all teams to have a moment of silence before each game on Sunday.

According to the New York Times, a 20-year-old man wearing dark clothes and armed with two handguns, opened fire inside of an elementary school where his mother taught, killing 26 people, including 20 children. Earlier, he had killed his mother and left her body at their home.

"It's awful, just an awful day. It really, really is," Boston Celtics coach Doc Rivers said before his team's game at Houston, according to ESPN.com. "This is our jobs. This is not a game for us, it is what we do but when something like this happens, it supersedes job and everything else. As a parent -- I don't know -- this is just awful, awful what happened."

Cavaliers head coach Byron Scott spoke about the tragedy on Friday.

"I have three healthy kids and a beautiful granddaughter," Scott said. "When you hear about kids who are that young and don't get a chance to live because of something that's so senseless as somebody going in and doing the things that this person did, I think it affects everybody. It puts everything in the right perspective as well. As much as we love this game, this doesn't mean nothing."

According to ESPN.com, the Brooklyn Nets showed on "the overhead videoboard at the Barclays Center a candle and the town seal of Newtown as the Nets and Pistons paused for reflection before their game in Brooklyn."

Kevin Durant took it upon himself to send a tribute to the families and the victims, writing "Newtown CT" on his right sneaker during Friday's game as the Thunder beat the Kings 113-103.

"I wish I could do more," Durant said of the message on his shoes. "But it hit me really hard. It's tough to see, especially kids that couldn't do anything for themselves. Words can't even describe it. I'm kind of at a loss for words right now."

Durant scored a game-high 31 points in the game and was emotional afterwards. Sports can be a way for some athletes to deal with their emotions and that was one thing that helped Durant on Friday.

"This is just crazy," Durant said. "I don't get it. That hit me, man. I'm sitting in the house all day. It was so gloomy out. It was so dark outside. I was like, 'Thank God we've got a basketball game tonight.'

Durant also tweeted: "Prayers go out to the families that were affected by the shooting in Connecticut, c'mon man this is too sad! Damn."

The NFL sent out memos to all 32 teams asking to observe a moment of silence for the victims. The league has done this before in the past.

"This shocking event has brought the nation together in grieving for the victims and their families as well as the survivors," the note read, according to ESPN.com. "We believe it is appropriate and important for us to collectively recognize and participate in the grieving process at our games this weekend, as we have done on other occasions."

Numerous NBA players and other athletes took to social media like Twitter and Facebook to try and process the tragedy and also to send out their wishes to the parents and victims of the tragedy, including Kobe Bryant and Deron Williams.

"I don't know if any of you have family, friends or connections to the horror that took place today in Connecticut. Let us all pray for them. The devastation is immeasurable," Lakers star Kobe Bryant wrote on his Facebook page, according to ESPN.com.

Miami Heat superstar LeBron James took to Twitter to express his feelings. James has been active in the Connecticut community, including donating the proceeds to his "The Decision" special to a Boys and Girls club in the area.

The Heat played against the Washington Wizards in Miami on Friday and coach Erik Spoelstra had a team meeting before the game to speak about the tragedy and everything involved.

"We took some time to give our thoughts and prayers to them," Spoelstra said. "You could hear them talk in the locker room, the looks on their faces. It wasn't something that we could just brush under the rug. We had to talk about it."

"At some point, we've got to get past bureaucracy and all the nonsense and do something about this so our kids can be safe," said New Orleans Hornets coach Monty Williams, who has five children ranging in age from 2 to 14. "If we can go to outer space and take care of trees and rivers and animals, we can do a better job of taking care of our kids. It's just a sad situation."

This is just the latest tragic event that has occurred recently. In the NFL, Kansas City Chiefs linebacker Jevon Belcher killed his girlfriend before committing suicide in a parking lot at Arrowhead Stadium. Dallas Cowboys defensive lineman Josh Brent also had an incident when he was charged with intoxication manslaughter on Dec. 8 after he flipped his car in an accident that killed teammate and friend Jerry Brown.

Here is more information on the shooting in Connecticut.