The UN's findings come days after reports first surfaced that several civilians had been killed in an airstrike in Boka village in northern Balkh province.

"UN gravely concerned as its initial findings indicate at least four children and two women killed Saturday by pro-government forces airstrike in Boka village, #Balkh, #Afghanistan," tweeted the United Nations Assistance Mission in Afghanistan (UNAMA).

The US and Afghan militaries are the only forces in Afghanistan that have the capability to carry out airstrikes in the country.

Balkh governor's spokesman Munir Farhad confirmed that civilians had been killed in Boka, but said officials were still investigating the incident.

The statement comes as Washington has for weeks been calling for the violence to be reduced in the country, amid talks with the Taliban over a possible agreement that would see US troops begin to leave Afghanistan in return for security guarantees.

Taliban sources told AFP earlier this month they had offered to initiate a brief ceasefire of seven to 10 days, but there was no announcement of the proposal by either party.

The Taliban are aiming to reach a withdrawal agreement with the US by the end of January and are prepared to "scale down" military operations ahead of signing a deal, their chief spokesman said earlier this month.

The two sides had been negotiating the deal for a year and were on the brink of an announcement in September 2019 when Trump abruptly declared the process "dead", citing Taliban violence.

Talks were later restarted in December in Qatar, but paused again following an attack near the US-run Bagram military base in Afghanistan.

Any agreement with the Taliban is expected to have two pillars -- a US withdrawal from Afghanistan and a commitment by the insurgents not to offer sanctuary to jihadists. It would ultimately have to win final approval from Trump.

Last month, UNAMA reported that more than 100,000 Afghan civilians have been killed or injured over the past decade -- a grim milestone after more than 18 years of war since US and NATO allies invaded the country following the September 11 attacks in 2001.

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