More than 50 other people injured in the accident had been taken to hospital in Ghazni province, officials say.
All three vehicles were set ablaze after the collision on the main road linking the capital, Kabul, to the southern city of Kandahar.
Accidents are common in Afghanistan where roads are often in a poor state.
The BBC’s Mahfouz Zubaide in the capital, Kabul, says drivers also tend to speed and traffic rules are rarely enforced.
Mohammadullah Ahmadi, the director of the provincial traffic department, said the crash was caused by reckless driving, the Associated Press news agency reports.
He said local residents helped fire fighters and first responders pull survivors from the wreckage.
Most of those who died in the crash were “completely burned”, health ministry spokesman Ismail Kawasi told the AFP news agency…….click to continue reading