The video taken by Free Burma Rangers shows helicopters firing at the ground and jets flying near the trenches of the rebel Kachin Independence Army, the BBC reported Wednesday.
The BBC obtained the video from the organization.
Witnesses confirmed the presence of government jets and helicopters in recent days in the restive area of the country formerly known as Burma. The number of casualties that occurred during the five days on attacks was unknown, the BBC said.
Zaw Htay, director of the president's office, said the situation was complicated and military leaders said the planes were being used to ferry in troops.
"The aircraft being used are K8 training aircraft not fighter jets; that is the information I got from the military," he said. "I have no information on the use of helicopters. There is a very difficult situation in Kachin state."
After a 17-year truce, fighting with the Kachin rebels resumed in 2011.
Many of the people living on the battlefront have fled to refugee camps in Kachin or across the border in China.