Two U.S. servicemembers were among the five people killed after a military helicopter crashed at the NATO base in Kabul, Afghanistan, authorities said Monday.

Two British servicemembers and a French civilian also died, according to the statement from the Resolute Support Mission. Officials said five other NATO personnel were hurt.

“We’re deeply saddened by the loss of our teammates,” said Brig. Gen. Wilson A. Shoffner, Resolute Support Deputy Chief of Staff for Communications. He added, “we pray for the full recovery of those injured.”

The British Ministry of Defense said the Puma Mk 2 helicopter crashed while landing at the headquarters of the NATO Resolute Support Mission, which is training Afghan security forces.

NATO officials said the helicopter "crashed due to a non-hostile incident" around 4:15 p.m. Sunday at Camp Resolute Support, Kabul.

The alliance said the incident is under investigation, but did not provide further details.

“We’re deeply saddened by the loss of our teammates.”

- Brig. Gen. Wilson A. Shoffner, Resolute Support Deputy Chief of Staff for Communications

Earlier, U.S. Army Col. Brian Tribus, a military spokesman, said an "incident" involving a NATO aircraft and an observational balloon had taken place "in the vicinity of the Resolute Support base."

The balloon was severed from its mooring in the incident, he said, without providing further details.

The helicopter appeared to strike the monitoring balloon as it landed at the NATO base, according to Najibullah, an Afghan security guard who witnessed the incident. Like many in Afghanistan, he goes by one name.

The helicopter "hit the cable of the security balloon over the base, It seemed like the cable was turned around the helicopter rotor," he said. Najibullah said the helicopter went down and then black smoke rose from the area.

A second helicopter circled around the area three or four times and then landed at a nearby airport, he said.

The Associated Press contributed to this report.