A helicopter crash in Peru killed seen people in the Amazon jungle, including 5 Americans.

The aircraft was operated by the local unit of U.S. based Columbia helicopters, says Peru's air transport agency, Corpac.

Reuters reported that five U.S. citizens and two Peruvians were on the helicopter and rescue crews were recovering their bodies. 

CNN reported that the team was working on an oil exploration operation near Pucallpa, Peru when the helicopter crashed.

"Minutes after the helicopter took off from the Pucallpa Airport, authorities lost communication with the pilot, and people in the control tower could see a heavy smoke column in the distance," reported CNN.

A company official has said that it is still unclear what has caused the incident. "We've notified all the authorities and are cooperating with everyone fully, and we'll do everything we can to learn any causes ... of the accident," said Michael Fahey, Columbia Helicopters president and CEO to CNN"It's a very sad day for us. We operate globally, but we're a family and we're very close to our employees. And I personally knew many of the individuals who died as our other employees know many of them," Fahey told reporters in Oregon. "We're grieving for them."

CNN reported that the victims on the helicopter were pilots and crew of Columbia helicopters. CNN reported that a police chief said that three of the bodies were found away from the crash site. Authorities believe that these three may have jumped from the plane before the crash.

"The two Peruvians killed in the crash were Igor Castillo and Luis Ramos. The Americans were identified as Dann Immel, Edwin Cordova, Jaime Pickett, Darrel Birkes and Leon Bradford," reported CNN.