The accident occurred around 10am in front of the Hiranyakandi Sampan Highway Restaurant on the Dhaka-Khulna highway, said Azizul Haque Rajan, station manager of Bhatiapara Fire Service.
The deceased were identified as Montu Sheikh, 55, the driver of Tungipara Express, and Arif Hossain, the bus supervisor.
According to fire service officials, the Tungipara Express bus first hit the rear of a Khulna-bound Sohag Paribahan bus and then hit the tree, leaving 12 people injured, including the driver and supervisor.
The injured were rushed to Kashiani Upazila Health Complex, where doctors declared Montu Sheikh and Arif Hossain dead, reports UNB.