Newtown School Shooting: Kim Kardashian, Lindsay Lohan, More Tweet About Tragedy at Sandy Hook Elementary in Connecticut

At least 26 dead, including 20 children, after a gunman opened fire in what is now the second-deadliest school shooting in U.S. history

Families, friends and loved ones, along with countless people across the nation, are in mourning after a gunman opened fire at Sandy Hook Elementary School in Newtown, Conn., Friday morning, killing at least 26 people including 20 children.

The gunman, whom authorities have identifed a Adam Lanza, has been reported dead in what is now the second-deadliest school shooting in U.S. history, following the 2007 massacre at Virginia Tech, which killed 32 people.

Celebrities immediately took to Twitter to express their shock and outrage at the horror that unfolded, and to send their condolences to the families involved.

Kim Kardashian: "In total shock over the school shooting in Ct!...What has this world come to…These kids come to school to learn, never expecting this tragedy to happen. They didn't deserve this. Praying for everyone involved!"

Lindsay Lohan: "This is absolutely horrifying. Our thoughts and prayers go out to the families in Newton, CT. So unbelievably sad."

Ashton Kutcher: "Overwhelming feelings of sadness for something so senseless. My heart goes out to those in Connecticut."

Jessica Alba: "This is just awful. My heart goes out 2 all affected... So sad."

Zooey Deschanel: "I am filled with sadness in the wake of the sandy hook school tragedy. My thoughts and prayers are with all in Newtown, Connecticut."

Blake Shelton: "Stand strong and stand united everyone... We are Americans and we are better than this. What a sad sad disgusting day this is...My heart is so heavy right now... I can't shake it off."

Demi Lovato: "Just in shock. WHAT is wrong with this world sometimes? Right before Christmas? My thoughts and prayers go out to Newton, CT."

Kristin Chenoweth: "Our hearts are broken for you, Newtown."

Joe Jonas: "This is such sad news. Heart is broken for the children and their families."

Jordin Sparks: "Those precious children...I will never understand the evil in this world. On my knees praying for those families. I am in tears."

Ian Somerhalder: "We are sad. Our hearts, thoughts & help are w/ you. Im so sorry to all affected by this. So sorry. May all the love in the world hug you in this time."

Miley Cyrus: "Why does this happen? Why do bad things happen to such good people... Especially young ones. Sending blessings to CT."

Jennifer Hudson: "Yal, we need to pray! This can't keep happening . My mama always said ' if u think you've seen it all just keep on living'."

Melissa Joan Hart: "How could someone be so evil as to kill innocent children at school? God Bless and watch over those families and children that witnessed it!"

Tom Arnold: "We need to focus more on these awful American terrorists. #SandyHook"

Bethenny Frankel: "These poor parents probably have Christmas presents for these poor babies. I can't stop crying."

Maria Shriver: "My heart is breaking as this story unfolds. Let's start a #circleofprayer for the children and their families."

Alyssa Milano: "My heart and soul aches for the parents of those babies lost and for the babies that have to somehow heal & overcome... Hold each other."

Omar Epps: "#PrayForNewtown! I'm really sick & tired of senseless violence impacting innocent children!"

Jon Favreau: "Heartfelt condolences to all touched by these tragic events."

Christina Applegate: "There are just no words. Only sorrow. We are all shedding tears today for those families."

Kelly Rowland: "My heart goes out to the parents & children of Sandy Hook Elementary School #PrayForNewton."

Kevin Spacey: "Just heard about the shooting in Connecticut. My thoughts go out to all who are dealing with this sad news.

Piers Morgan: "Don't just mourn these poor dead children America - get angry and do something to stop these senseless shootings happening."

Holly Robinson Peete: "This story has me paralyzed with sorrow... #SandyHookElementary the reports of deaths are unfathomable... #RIP to the angels lost #senseless."

Courteney Cox: "Praying for Sandy Hook."

Joan Rivers: "Hearing the news of the sad tragedy in CT. I'm horrified and heartbroken - my thoughts and prayers are with the victims and their families."

Eva Longoria: " My heart sinks as I hear the news of the Sandy Elementary shooting in CT...God Bless everyone and their families!!!"

Jodie Sweetin: "I can't stop crying... This news of the tragedy in Connecticut is beyond words. I am sending prayers 2 families. My heart breaks for them."

Michael "The Situation" Sorrentino: "I can't even begin to imagine what those poor parents and children are going through in CT. My heart goes out to everyone affected."

Ashley Greene: "Some things are just bigger than me and impossible for me to understand. My thoughts and prayers are with the families in Connecticut."

Snoop Dogg: "Sending love 2 the families in Connecticut for their tragic loss. 2day I bow my head in sadness."

Josh Groban: "My heart is crushed with the news of this shooting."

Katharine McPhee: "I'm so saddened over the shootings in CT. In light of such an evil act, #PrayForNewton."

Kevin Bacon: "Just sick about the news from CT. Sending love to all those families."

Brooke Burke-Charvet: "Unfathomable news in Connecticut. I have no words. Holiday spirit just got sucked out of me. I'm sick.."

Lea Michele: "There are no words to express the sadness of this unthinkable tragedy. Sending my prayers to the families in Newton CT."

Pee Wee Herman: "My heart goes out to the victims and families in Connecticut affected by the senseless tragedy. I'm heartbroken."

Lisa Vanderpump: "Utterly devastating to hear of this catastrophic event,god bless the families..one will never comprehend the motivation behind this..so sad"

(Originally published Dec. 14, 2012, at 12:20 p.m. PT)