KABUL,  Afghanistan  — An airstrike by United States-led forces caused a large number of civilian casualties after it hit a wedding party in Kandahar Province in southern Afghanistan, Afghan officials said Wednesday. The casualties included women and children, the officials said.

The United States military and Afghan authorities were investigating the reports about the attack, the American military said in a statement, but there was no confirmation of the strikes or any death toll.

“The coalition and Afghan authorities are investigating reports of non-combatant casualties in the village of Wech Baghtu,” said Cmdr. Jeff Bender, deputy public affairs officer of United States forces in Afghanistan, in a statement.

“If innocent people were killed in this operation, we apologize and express our condolences to the families and the people of Afghanistan,” he said, adding that the facts were “unclear at this point.”

Zalmay Ayoby, a spokesman for the governor of Kandahar, said the incident took place on Monday afternoon when  Taliban  and coalition forces engaged in a firefight near Wech Baghtu village in Sha Wali Kot district. An airstrike later hit a compound where a wedding party was being held, he said.

“Unfortunately we should say that an airstrike on a wedding party had killed and injured a huge number of people in Sha Wali Kot,” he said.

Ahmad Wali Karzai, brother of Afghanistan’s president  Hamid Karzai  and leader of the provincial council in Kandahar, said there were civilian casualties but he said it was unclear how many people had died.

He said he had spoken with some people who had been wounded in the attack and had been admitted to Kandahar’s main hospital. They told him that as many as 32 civilians were admitted, including women and children from the wedding party, he said.

Dr. Qudratullah Hakimi, a doctor at the Merwais Hospital in Kandahar, who was reached by telephone, said the hospital had admitted 22 women and six children after the attack. The children were aged between one and 11 years old, he said. He said the bride from the wedding party was among those injured and had undergone an operation but was stable.

“Five out of 28 are in serious conditions and the others are stable,” he said. His patients reported that up to 90 people were killed or wounded in the attack, and that some were buried under the rubble, although this could not be confirmed.

Later, Mr. Karzai, the president, said that around 40 had been killed and another 28 wounded, according to Agence France-Presse.

Afghan anger over airstrikes and civilian casualties has been rising amid tensions with the United States.

In one of the most controversial recent cases, an American AC-130 gunship attacked a suspected Taliban compound on Aug. 22, prompting assertions by villagers that more than 90 civilians were killed, a majority of them women and children.

In that attack, the American military initially said five to seven civilians were killed, but a subsequent report by a military investigator put the civilian death toll at more than 30.

In a news conference Wednesday, Hamid Karzai, the Afghan president, referred to civilian casualties in the alleged attack on Sha Wali Kot and said an end to casualties in Afghanistan was an initial demand on the new president-elect,  Barack Obama.

“The fight against terrorism cannot be won by bombardment of our villages,” Mr. Karzai said. “My first demand from the new president of the United states when he takes his office will be to end the civilian casualties and take the fight to where the nests and sanctuaries are,” he said.