The accident occurred at about 6 am in Thuong Tin District when the 60-seated Thanh Van bus hit a Laos bus running from Savannaket to Hanoi which was running the same lane.
At the site, both buses were heavily damaged.
Ambulances are sent to take injured passengers to hospital.
According to an official from the Hanoi Traffic Police Department, more than ten passengers have been injured in the accident and have been rushed to local hospitals.
The accident caused serious traffic jam in the highway.