TEHRAN, Iran — A landing Iranian passenger plane skidded off the runway and raked its wing along the ground, sparking a fire that killed 29 of the 148 people on board Friday in the latest deadly crash of a Russian-made aircraft.

State television reported that a tire exploded as the plane landed, but the spokesman for Iran's Civil Aviation Organization, Reza Jafarzadeh, said investigators had not confirmed that and it was still not clear what caused the plane to slide off the runway.