KABUL — The NATO mission in Afghanistan has opened a preliminary investigation into reports that 22 civilians were killed in recent US airstrikes in the southern province of Helmand, military officials said Saturday.

Elders from the Sangin district, the scene of heavy fighting in recent weeks, with the Taliban blowing up Afghan army posts there, have said that multiple US airstrikes early Friday killed nearly two dozen civilians, including several women and children.

Brigadier General Charles H. Cleveland, a spokesman for the US-led NATO mission, insisted that the military command had seen no conclusive evidence that civilians were killed in the airstrikes, but said “a formal review to determine the credibility of the claims’’ had been opened. The investigation team involved NATO officers outside the US command to ensure impartiality, he added.

“We are absolutely investigating this, and we take claims of civilian casualties seriously, although at this point we have no indication at all that civilians were killed,’’ Cleveland said.

Relatives of the victims, however, provided a different account.

Hameed Gul, 18, who sells soft drinks in Lashkar Gah, the provincial capital, said nine of his family members in the village of Lakari in the Sangin district were killed by the airstrikes. He and one of his brothers, who was also in Lashkar Gah, are the only surviving members of their family, he said. Their father, Mullah Pacha, was killed in an explosion years ago.

“My elder brother and I traveled to the village to find out how our mother, brothers and sister have been killed,’’ Gul said. “When we arrived, the villagers were digging them out of the debris.’’

Gul said fighting around his village had forced his family to move to Lashkar Gah, but his mother and siblings had returned to Sangin about three months ago because violence had intensified in the Lashkar Gah area.

Hajji Mohammad Dawod, an elder from the Sangin district who had fled to Lashkar Gah, said that another attack struck the house of Malim Faida Mohammed, killing him and 12 family members: his two wives, two of his daughters-in-law and eight of his children.

Dawod said the airstrikes destroyed houses near a mosque where Taliban fighters were staying, and killed civilians. The toll, he said, was also confirmed by people who attended the burials.

“There is no doubt that the civilians have been killed, and the government should not hide it or deny,’’ he said. “This is not fair.’’

A report released by the mission last week said that in 2016, airstrikes by international and Afghan air forces had caused 590 civilian casualties (250 deaths and 340 injuries), the highest toll since 2009 and nearly double that recorded in 2015.

Afghan government officials in Helmand on Saturday continued to reject reports that civilians had been killed in Sangin. But their reasoning also underscored the government’s shrinking control there, as the Taliban have essentially seized all the territory right up to the gates of the government compound in Sangin.

“The area targeted is free from civilians — there’s no resident within 3 kilometers of the district center, and the airstrikes were conducted 700 meters from the district compound, where no civilians are able to live in that close range of the battleground,’’ Hayatullah Hayat, the provincial governor, said in Lashkar Gah. He said about 60 Taliban fighters were killed in the airstrikes.

In a sign of how bad the fighting in Sangin is, the United States alone has carried out about 30 “air-to-ground’’ attacks in the district over the past week — a term that includes airstrikes as well as ordnance fired from helicopters, Cleveland said.

The Afghan air force has also been engaged in recent battles, but officials would not comment on the exact number of strikes its aircraft had carried out in Sangin. In all of Helmand, the Afghan air force conducted 114 airstrikes in the past three months, said a Defense Ministry spokesman.