KABUL, Afghanistan (CNN) -- Afghan President Hamid Karzai has ordered an inquiry into allegations that 15 civilians were killed in a U.S. military strike targeting militants.
The probe into Friday's incident on the border of Konar and Nurestan provinces came as local officials said another coalition bombing in eastern Afghanistan on Sunday killed at least 23 people and wounded 10 others who were walking to a wedding party.
U.S. military Capt. Christian Patterson said he had heard no reports that civilians had been killed in Friday's incident.
Karzai's office was told that attack killed 24 militants, spokesman Siamak Hirawi said Sunday, but he said local officials alleged 15 civilian lives were lost. Karzai called for an investigation to sort through the conflicting reports, Hirawi said.
Among the civilians that were reportedly killed in Friday's U.S. helicopter attack were five members of one family: a doctor and at least two children, the spokesman said.
A spokesman for the U.S.-led coalition said he was aware of reports regarding Sunday's military strike but had not received reports that civilians were killed.
The coalition bombing Sunday occurred at about 6:30 a.m., said Hamisha Gul, district governor of Deh Bala district of Nangarhar Province, where he said the incident took place.
"The wedding party was supposed to be going from one village to another to take the bride to the house of the groom," Gul said. "You will have to ask the Americans whether these were terrorists. So far as I know they were men, women and children traveling to a wedding."
The incident is still under investigation, according to Col. Tanwar, the head of the anti-terror police unit in Nangarhar. He noted that the time of the incident "seems very early for a wedding party."
"We expect to receive more details in a couple of hours," Tanwar said.
Patterson told CNN said that combatants were killed but that there was "no information that civilians were killed in that incident."
Karzai has stepped up pressure on his U.S. allies to take more precautions when carrying out military operations against the Taliban in Afghanistan.
In July 2002, a U.S. military airstrike in Oruzgan Province killed at least 34 people at a wedding party, prompting outrage among the Afghan people.
Local Afghans said that U.S. forces confused "celebratory fire" from wedding participants for hostile fire, but the U.S. military found that several compounds in the Deh Rawod area were "positively identified" as sources of anti-aircraft fire.
Deaths of ordinary Afghans caused a huge outcry last year, but there have been fewer accusations of such killings in recent months.
The United Nations said the proportion of Afghan civilian deaths blamed on government forces and U.S. and NATO troops has declined in the first six months of 2008, largely due to pressure from Karzai's government.
"It is clear that the international military forces are making every effort to minimize civilian casualties and recognize the damage this does and want to deal with that," U.N. undersecretary-general for humanitarian affairs John Holmes said last month.
"Nevertheless, these problems are still there, and we need to deal with them and make sure that the safety of civilians comes first and international humanitarian law is respected by everybody."
More than 2,100 people -- mostly militants -- have been killed in insurgency-related violence in Afghanistan this year. More than 8,000 people died in attacks last year, according to the U.N., the most since the 2001 U.S.-led invasion.
CNN's Atia Abawi and Journalist Tom Coghlan contributed to this report.