Five girls have died and several others have been badly hurt after a shooting at their school in America.
The attack happened in a very small school and the pupils came from a group of people known as the Amish.
The Amish community is very against violence, which is why this shooting is very surprising.
Do you have a message for the people affected by this attack?
Maybe you'd like to show your sympathy to the families or children involved.
E-mail and tell us here.
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I feel very sorry for the Amish community.
Eleanor, 11, Galway
I have visited the Amish community many times. It's an amazing place with some lovely people. I just can't think how someone could do this!
Amelia, 12, Salisbury
It's horrible someone could do that to some poor innocent children.
Didier, 12, France
This is amazingly awful. Why would anyone do this? This has not just caused upset to the families of the girls that were shot but it has shocked the whole world. Sometimes the world can be cruel and unfair.
Erica, 11, Poole
I feel very upset by this news. No wonder the gunman killed himself after it, it's so shameful. I feel really sad for the families and just hope nothing like this ever happens again!
Ailsa, 12, Glasgow
This is really bad and I wish I could do something for the people who are hurt.
Natalie, 9, Hong Kong
I have been to Lancaster County were it happened and have seen the Amish before. I remember waving to them and they waved back to me. Now I am going to have the people who died in my prayers.
Olivia, 12, USA
How could anyone do that? What did the Amish girls do to him? It's so frightening to think that anyone any day could just walk into your school and do what that man did to those children. I feel really sorry for the families.
Fionnuala, 12, Ireland
I feel very bad for the people who got hurt or killed.
Charlotte, 9, Thailand
How could someone do that? It is just evil and unfair. Try and imagine how the families must feel. I know I can't imagine the horror of that!
Annabel, 11, Pollington
Why Does the world have to be like this? What are people achieving by killing others?
Rhys, 11, Winchester
I'm so sorry for the girls that died and their families. They're not alone in feeling bewildered, hurt and indeed very angry. My thoughts and prayers are with the Amish at this very difficult time.
Charis, 14, London
I can't believe someone would do something like this. He must have been mad.
Liam, 11, Hull
All this stuff about shooting kids makes me feel very sick - it's disgusting. I feel so sorry for the parents of the children but at least it was on a small scale after what happened in Beslan in 2004.
Taylor, 14, Swindon
Why would anyone want to attack such a peaceful place? They've never done anything to anyone. I feel really sorry for the families of the girls who died.
Neven, 12, Swansea
My sympathy goes to all of them. I recently visited an Amish community in America and they're really nice people. It's really sad someone would do this to young girls who know nothing about violence.
Fatimah, 12, London
My thoughts are with the families of the girls who were hurt and killed. I feel so sorry for them, it isn't right to hurt and kill others.
Emily, 12, Newcastle
I am very sorry to hear this and I send my deepest sympathy to the families and friends affected by this terrible incident.
Charlotte, 13, Gloucester
I am shocked about this and I can't believe that someone would do such a thing. I feel sorry to all the people who were there.
Michael, 12, Birmingham
I think it's really shocking and my heart goes out to all the parents of the kids.
Alfie, 11, London
I feel sorry for all the people affected by it.
Gabbi, 11, Portugal
I feel really upset and sad.
Uzma, 11, Walsall
There are more angels in heaven. Bless them and bless their families and friends.
Lauren, 12, Ireland
I can't believe someone could do something like this. It's pure evil. I can't even begin to imagine how upset the families of the children must be.
Martha, 11, Bristol
I was very shocked to hear about this. My thoughts are with their families.
Kennedy, 10, Bradford
I feel sympathy for all the families who have lost a loved one or a friend.
Harpreet, 10, Chigwell
I was all choked up when I read about this. I feel very sorry for them and their families.
I was horrified when I found out. I think there should be a memorial at the school for the four girls.
Rob, 13, Nantwich
It's not fair about what has happened. I feel sorry for them all.
Daniel, 12, Hemsworth
I was really shocked when I heard this on the news, especially as it was all girls who were hurt. I hope all the other children in the town are OK.
Tamsin, 11, Portishead