KABUL, Afghanistan -- An investigation into claims that international troops killed scores of civilians in northeast Afghanistan escalated into a feud Tuesday between President Hamid Karzai and senior U.S. military officials who cited a report that Afghan parents have been known to discipline children by burning their hands and feet.

Karzai spokesman Waheed Omar described comments made by Rear Adm. Gregory Smith, director of communications for the U.S.-led coalition, also known as International Security Assistance Force, as being "outrageous, insulting and racist." He demanded a clarification.

The flap started during a discussion at the presidential palace about claims that NATO forces killed about 60 civilians during a four-day operation in Kunar province -- a charge that has been contested by the international coalition.

Media reports and television footage broadcast after the claims showed severely injured children and others with burns on their faces, hands and feet -- yet is was unclear if they were injured in military operations.

The Washington Post, quoting unidentified individuals who attended the palace meeting, reported Tuesday that Gen. David Petraeus, the top NATO commander in Afghanistan, had suggested that Afghans might have intentionally burned their own children to exaggerate claims of civilian casualties.

The coalition vehemently denied the report.

"Gen. Petraeus never said that children's hands and feet were purposely burned by their families in order to create a CIVCAS (civilian casualty) event," Smith said. "Rather, he said that the injuries to the children appeared inconsistent with the types of munitions used and that the burns to their hands and feet may have been the result of discipline sometimes handed out to Afghan children. Regrettably this is customary among some Afghan fathers as a way of dealing with children who misbehave."

Omar said that Karzai was demanding an explanation.

"The president was extremely annoyed by the comments made by Adm. Smith that Afghans boil the hands and feet of their children to discipline them and we find these comments outrageous, insulting and racist," Omar told The Associated Press.

"Afghans love their children and to suggest that Afghans boil the hands and feet of their children suggests a lack of information or ... someone's feeling for Afghans. We want NATO and the ISAF leadership to take serious note of these comments and the president will ask for clarification from ISAF in this," he said.

Omar added that "on the one side, Afghan children and women are killed brutally by terrorists and on the other side they are insulted in this manner."

Although relatively unheard of, there have been some such incidents reported in the past. A 2009 human rights report issued by the U.S. State Department said that "in extreme examples of child abuse, observers reported several instances of deliberately burned children in Paktia (province); the children sustained burns after their parents submerged them in boiling water."

Earlier in the day, a government delegation, sent by Karzai, met with tribal elders from the remote Ghazi Abad district, and other provincial officials to investigate the claims of civilian casualties.

Nawrdin Safi, a provincial council member from Kunar who attended the meeting, said tribal elders repeated their allegation that "more than 60 people have been killed in the four days of the operation and around 50 of that number are civilians, including women and children."

He said that the delegation was discussing a trip to Ghazi Abad.

"We have to go personally to the site to find out what's really going on and what number is correct, and how many of those killed are really civilian. ... The real investigation will be at the site," Safi said, adding that the delegation would also examine grave sites. "Hopefully we will be able to determine exactly how many have been killed."

The coalition, which also is investigating the allegation, has said video of operations on Feb. 17 -- the main event of a more than three-day operation -- showed troops targeting and killing dozens of insurgents, not civilians.

"We are reviewing all operations, to include several involving the use of fighter aircraft that dropped various munitions on other remote mountainous areas in the Ghazi Abad district prior to and after this event," Smith said.

"The review of these engagements is still under way, so there's always the possibility one of them may have resulted in civilian casualties, but reports from elders in the region appear unrealistically high and unsupported by anything we know to date. The work of the joint assessment team is still ongoing, so no final judgments are being made at this time."

Smith said video of the Feb. 17 operation showed no women, children or buildings near the site of the attacks against the insurgents.

"In all, we estimate somewhere around 40 armed insurgents were killed by coalition air," Smith said.

Afghan and coalition officials also are investigating how the civilians, filmed being treated at a hospital in the provincial capital of Asadabad, were injured.

The director of the health department for Kunar province, Assadulah Fazeli, said all their injuries were caused by a bomb and none were deliberate. He added that what burns they had were consistent with an explosion. All the patients are from Ghazi Abad district, but Fazeli said he did not know where or when they had been injured.

"They are all from the same family and all the injuries they have are multiple wounds from a bomb," Fazeli said. "This has been determined by the doctors in the hospital that the wounds are from an air strike and each one of these patients has multiple wounds on different parts of their bodies."

A recent U.N. report documented 2,412 conflict-related civilian casualties in the first 10 months of 2010. More than three-quarters of them were caused by militant activity, a 25 percent increase from the same period in 2009, the report said. At the same time, civilian casualties attributed to pro-government forces, including those from the NATO coalition, decreased.