Top music stars are among those reacting with horror via Twitter to the news that more than 27 people, mostly elementary school children, were shot and killed by a gunman at a Newtown, Connecticut, school this morning.  Here's a look at what they had to say:

Rihanna -- God have mercy!!!! No one deserves this! Praying for the families of the victims of the Connecticut shooting!! What a Christmas it will be

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.

OneRepublic -- Our hearts and prayers go out to the families, kids and teachers at the Connecticut school shooting - this insanity, this EVIL has to end

Neon Trees ' Tyler Glenn -- Absolutely crushed, in my heart, reading these school shooting reports. Crushed at the death of so many kids in such a heinous way no less.

Josh Groban -- Oh my lord. Just turned on the news, I've been on a technology free bike ride. My heart is crushed with the news of this shooting.

Demi Lovato ( demetria lovato) -- My heart is absolutely broken after hearing about the shooting at Sandy Hook Elementary school.. Wow.. So terrible.

Kings of Leon 's Nathan Followill -- Just saw the tragic news about the school shooting. As a soon to be father this is tragic. My thoughts & prayers are with the families. # sad

Kevin Jonas -- To everyone involved in the shooting Connecticut our thoughts and prayers are with you this is truly a tragedy.

Andy Grammer -- Really upset to hear about Newtown... Love and prayers for everyone suffering

Ellie Goulding -- Man I can't even comprehend the shooting in Connecticut, it's just the saddest thing... So hard to understand

Lady Antebellum -- Our thoughts and prayers go out to all the families and everyone affected in Connecticut. # newtown

Jay Sean -- just heard about the tragic incident in Connecticut. it makes me ill to think there are such sick minded people that we have to live amongst.

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