Defense Secretary Leon Panetta joined the gun control debate on Thursday when he told troops at a military base in Italy that only soldiers needed armor-piercing bullets or assault weapons.
Asked by a soldier what President Barack Obama would do to protect school children from gun violence without infringing Americans' right to own guns, Panetta said action was needed after the attack on a Connecticut school in December in which a gunman killed 20 children and six adults.
He told members of the 173rd Airborne Brigade Combat Team at Vicenza that there were areas where steps could be taken,
"I mean who the hell needs armor-piercing bullets except you guys in battle?"
In the aftermath of the Connecticut shooting - the latest mass killing in the United States on a list that includes Columbine in 1999 and Virginia Tech in 2007 - Obama launched the biggest gun-control push in generations.
He asked Congress on Wednesday to approve an assault weapons ban and background checks for all gun buyers.
Panetta, who is on a week-long trip to Europe, was President Bill Clinton's chief of staff when the United States banned the sale of assault weapons in the 1990s.
"Unfortunately that ban went out of effect," he said.
He added that he was an enthusiastic hunter.
"I've been duck hunting since I was 10-years-old. I love to hunt and I love to be able to share that joy with my kids. But for the life of me, I don't know why the hell people have to have an assault weapon."
Panetta said the administration must take measures to protect children from gun violence at school.
"I think this can be done. I think steps can be taken that will not undermine the Second Amendment and at the same time try to protect some of our schools so that the nuts that are out there won't use these kinds of weapons to wipe them out," he said.
The Second Amendment of the U.S. Constitution gives Americans a legal right to own firearms.