Two Afghan army helicopters collided while transporting wounded soldiers in the southern Helmand province, killing nine Afghan service members.
The two Soviet-era Mi-17 helicopters crashed due to technical problems while taking off in Nawa district, the Afghan defence ministry statement said.
The nine fatalities were all Afghan crew and soldiers who had been on board the aircraft.
A spokesman for Helmand’s provincial governor said the helicopters were carrying wounded soldiers when they crashed late on Tuesday.
He said that over the past week, Taliban fighters have launched coordinated attacks in different parts of Helmand province which have intensified in recent days.
Three local officials in Helmand province said the helicopters were deploying Afghan commandos to repel a Taliban attack in Nawa district, and were evacuating wounded soldiers on their return flight.
The Afghan officials spoke on condition of anonymity because they were not authorised to speak to the media about military activities.
On Monday, American forces said they had carried out several airstrikes in Helmand province in support of Afghan security forces under attack by the Taliban.
Colonel Sonny Leggett, a spokesperson for the US military in Afghanistan, said on Monday that the recent Taliban attacks in Helmand were "not consistent" with a US-Taliban deal signed in February and undermine ongoing intra-Afghan peace talks.
He said the air strikes do not violate the February deal.
Separately, three civilians were killed and 14 wounded in the eastern province of Laghman by a magnetic explosive device attached to a police vehicle, said Shafiullah Afghanyar, a provincial police spokesman.
No-one immediately claimed responsibility for the attack.
Last week, US President Donald Trump said the remaining American service personnel in Afghanistan could leave the country by Christmas.
Mr Trump has previously promised to remove troops from "endless wars", generating fears the policy could leave behind power vacuums.
Currently there are nearly 1,000 UK troops deployed in Afghanistan.
British troops are stationed in Kabul where they take the lead within the Kabul Security Force.
Earlier this week, soldiers from 2nd Battalion The Royal Regiment of Scotland set off from their base to deploy to Afghanistan.
The unit left Glencorse Barracks in Penicuik on Tuesday morning for RAF Wittering, where they will undergo a period of quarantine under coronavirus restrictions before flying out to Kabul.
Cover image: A library image of the Gardez mountains in Afghanistan (Picture: NATO).