US President Barack Obama says American soldiers shown in photos apparently abusing Afghan corpses in 2010 should be held accountable, a spokesman said.
"The conduct depicted in those photos is reprehensible," White House spokesman Jay Carney told reporters.
The pictures, published in the Los Angeles Times, shows the soldiers posing with the mangled remains of suspected suicide bombers.
Mr Carney also expressed disappointment that the Times published the photos.
It comes at a particularly sensitive time for US-Afghan relations, after a series of incidents - including the murder of 17 Afghan civilians in March - stirred up anti-Western sentiment.
Nato combat troops aim to leave Afghanistan in 2014.
During a Nato conference in Brussels on Wednesday, Defence Secretary Leon Panetta apologised "on behalf of the Department of Defense and the US government".
"I know that war is ugly and it's violent and I know that young people sometimes caught up in the moment make some very foolish decisions," Mr Panetta added.
"I'm not excusing that behaviour, but neither do I want these images to bring further injury to our people and to our relationship with the Afghan people."
The pictures in the Los Angeles Times newspaper apparently show soldiers from the 82nd Airborne Division posing with the remains in Afghanistan's eastern Zabul province.
Some are seen grinning next to the bodies, while others appear to be holding severed human legs.
Another set of photos - from a few months later - apparently shows soldiers from the same division holding a dead man's hand with the middle finger raised.
The Los Angeles Times only published two of 18 photos.
It said the pictures had been given by a US soldier "to draw attention to the safety risk of a breakdown in leadership and discipline" among American troops.
The depicted soldiers - who have not been identified - had seen friends killed or wounded in suicide and other bomb attacks in the course of their year-long deployment, the paper said.
The Times defended its decision to publish the photos, despite a prior request from the US military not to do so.
"After careful consideration, we decided that publishing a small but representative selection of the photos would fulfil our obligation to readers to report vigorously and impartially on all aspects of the American mission in Afghanistan, including the allegation," the paper's editor Davan Maharaj said.
The commander of the International Security Assistance Force in Afghanistan (Isaf), Gen John Allen, has condemned the actions of the soldiers, while the US Ambassador to Afghanistan, Ryan Crocker, labelled them "morally repugnant".
The BBC's Paul Adams in Washington says the Americans have found themselves on the back-foot after a slew of negative publicity in recent months in Afghanistan.
Last month, a US soldier was charged with the murders of 17 Afghan civilians - including nine children - in the southern province of Kandahar.
In February, thousands of Afghans held street rallies after US soldiers inadvertently burned copies of the Koran at a Nato base in Kabul.
More than 30 people died in the ensuing unrest, as people protested at US bases and diplomatic missions.
A month earlier, a video emerged apparently showing US Marines urinating on dead Afghans.
The Taliban called off peace talks in the wake of that rampage and threatened more attacks.