The United States has strongly condemned photographs of soldiers posing with the mangled remains of Taliban insurgents in Afghanistan, launching an investigation and vowing to punish the culprits.

The photos, which date back to 2010 but were published by the LA Times on Wednesday, add to a string of recent scandals that have ignited anti-Western feeling and complicated NATO-US efforts to build towards a 2014 withdrawal.

US Defense Secretary Leon Panetta said those responsible would be punished but voiced "regret" that the LA Times had decided to publish the images against his wishes, warning that they could prompt a violent backlash.

"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," Panetta told a NATO press conference in Brussels.

"I'm not excusing that behavior, but neither do I want these images to bring further injury to our people and to our relationship with the Afghan people."

The LA Times published two of 18 photographs it was given by a soldier who believed they pointed to a breakdown in leadership and discipline that compromised the safety of the troops.

One showed a soldier with a dead insurgent's hand draped on his right shoulder. The other showed soldiers grinning and giving a thumbs-up behind the disembodied legs of a Taliban fighter.

The Times said another set of photos, which it has not yet published, show soldiers from the same division holding a dead man's severed hand with the middle finger raised.

The first incident took place in February 2010, when paratroopers from the 82nd Airborne Division were sent to an Afghan police station in Zabul province to inspect the remains of an alleged suicide bomber.

The soldiers had intended to try to get fingerprints and possibly scan the irises of the corpse, but instead they posed for pictures next to the Afghan police, holding up or squatting beside the remains, the LA Times reported.

A few months later, the same platoon went to inspect the remains of three insurgents whom Afghan police said had blown themselves up by accident.

NATO chief Anders Fogh Rasmussen denounced the photos but said it did not represent the values of the alliance's military mission.

"These events took place apparently a couple of years ago and I consider them an isolated event," he said.

White House spokesman Jay Carney said the photos were "reprehensible" but also said President Barack Obama's administration was "very disappointed" that the LA Times had published them.

The newspaper's editor, Davan Maharaj, said he had decided to publish a "small but representative selection" of the images because of their news value and to "fulfill our obligation to readers to report vigorously and impartially on all aspects of the American mission in Afghanistan."

The episode seemed likely to test already frayed US-Afghan relations, after a series of incidents in which US troops have been accused of misconduct.

The release in January of video clips online showing American marines urinating on the bodies of Afghan combatants sparked outrage in Kabul.

That was followed by the inadvertent burning of Korans by US soldiers in mid-February, which triggered anti-US protests that claimed 30 lives and may have motivated a surge of "insider" attacks on NATO troops by Afghan forces.

In March, a US soldier allegedly went on a shooting rampage in two Afghan villages, killing 17 people -- mostly women and children -- in what is believed to be the deadliest war crime by a NATO soldier in the decade-long conflict.

NATO has a 130,000-strong military force fighting the Islamist Taliban, which has led an insurgency against the Western-backed Kabul government since being toppled from power by a 2001 US-led invasion.

Afghan forces are gradually taking over control of security in the country, with the goal of being in the lead nationwide next year and enabling most foreign troops to depart by the end of 2014.