The crash occurred in Van province's Muradiye district near the Turkish border with Iran, where the vehicle caught fire after tumbling into a ditch.

The identities of those killed in the accident were not immediately clear. 

The owner of the bus was detained.

Turkey has been a key transit point for migrants aiming to cross into Europe. Migrants, mostly from Iran, Afghanistan and Pakistan, regularly cross the Iranian border into Turkey on foot before being ferried west to cities such as Istanbul and Ankara.