Two Afghan army helicopters collided while transporting wounded soldiers in the southern Helmand province, killing nine Afghan service members, the country's Defense Ministry and local officials said Wednesday.

The two Soviet-era Mi-17 helicopters crashed due to technical problems while taking off in Nawa district, the Afghan Defense Ministry statement said. The nine dead were all Afghan crew and soldiers who had been on board the aircraft.The incident is under investigation.

Omer Zwak, a spokesman for Helmand's provincial governor, said the helicopters were carrying wounded soldiers when they crashed late 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 authorized 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. Col. Sonny Leggett, a spokesperson for the U.S. military in Afghanistan, said Monday that the recent Taliban attacks in Helmand were "not consistent" with a U.S.-Taliban deal signed in February and undermine ongoing intra-Afghan peace talks.

He said the airstrikes do not violate the February deal. Thousands of Afghan civilians have fled Nawa and Nad Ali districts because of the fighting, said Atiqullah, a local community leader from Nawa district, who like many Afghans goes by just one name.

"Nothing is left to us, we lost everything, including our home, property and livestock," he said. He and his family fled to stay with relatives in the city of Lashkar Gah, Helmand’s provincial capital.

"The Taliban have launched attacks against security checkpoints, and they control most parts of Nawa district," he added.

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.

Around 35,000 people have fled heavy fighting in Helmand province in recent days, with the United Nations estimating on Tuesday that around 200 have been killed or injured during the massive Taliban offensive.