'Chernobyl Diaries' -- Horror Flick RIPPED By Victim Support Group

The new Jesse McCartney horror flick "Chernobyl Diaries" is a slap in the face to the 400,000 victims of the real-life nuclear disaster ... so says a Chernobyl recovery organization.

For those unfamiliar with the Chernobyl disaster ... (shame on you if you're one of them) ... scores of people were killed or disfigured when the nuclear power plant exploded in the Ukraine in 1986.

Now, the Friends of Chernobyl Centers U.S. tells TMZ ... it's furious with the plot of the new movie -- in which several people who were mutated in the blast hunt down unwitting tourists.

"It is terrible that such a tragic event as Chernobyl is being sensationalized in a Hollywood horror film," a rep for the org tells us.

"Thousands of people have died and over 400,000 people were evacuated from their homes. Today over 5 million people still live on contaminated land. The horror is not mutants running around, the real horror is the effect that Chernobyl continues to have on the lives of millions who have been devastated physically, emotionally and economically."