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The helicopter was landing at the hospital when it crashed

A critically injured patient was taken to another hospital for treatment

CNN  — 

A medical helicopter crashed at a hospital parking lot in eastern Oklahoma on Tuesday evening, killing one person and injuring three others.

The helicopter was landing at the Choctaw Nation hospital in Talihina when the incident occurred, said Brandy Griffin, a spokesman for Choctaw Nation Health Services.

One person, who was critically injured, was taken to another facility while two others were being treated in Talihina, he said. All the casualties were aboard the helicopter.

Talihina is 110 miles southeast of Tulsa.