While the Oscar-nominated film starring Bradley Cooper as a character based on former Navy SEAL Chris Kyle was taking in a record $105.3 million over the holiday weekend, Moore quickly tried to explain his tweets by posting a longer statement on Facebook.
"I didn't say a word about 'American Sniper' in my tweets," Moore wrote on Facebook.
"Here's what I think about American Sniper': Awesome performance from Bradley Cooper. One of the best of the year. Great editing. Costumes, hair, makeup superb!"
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My uncle killed by sniper in WW2. We were taught snipers were cowards. Will shoot u in the back. Snipers aren't heroes. And invaders r worse— Michael Moore (@MMFlint) January 18, 2015
But if you're on the roof of your home defending it from invaders who've come 7K miles, you are not a sniper, u are brave, u are a neighbor.— Michael Moore (@MMFlint) January 19, 2015
Newt Gingrich was among many notable figures who reacted strongly to Moore's tweets.
Moore said his tweets were based on what his father told him after serving in the South Pacific in World War II.
Moore posted on Facebook, "His brother, my uncle, Lawrence Moore, was an Army paratrooper and was killed by a Japanese sniper 70 years ago next month. My dad always said, 'Snipers are cowards. They don't believe in a fair fight. Like someone coming up from behind you and coldcocking you. Just isn't right. It's cowardly to shoot a person in the back. Only a coward will shoot someone who can't shoot back.'"