A first crash involving a bus and an ambulance killed 16 people and injured 21 more in Gaziantep province, local media said.
Governor Davut Gul earlier said the accident had involved “a bus, an emergency team and an ambulance” on the road between provincial capital Gaziantep and Nizip.
The DHA news agency said a passenger bus had crashed into an ambulance, a firefighting truck and a vehicle carrying journalists at the site of a previous crash.
“Three firefighters, two emergency workers and two journalists figure among the dead,” the Gaziantep governor said.
Photos on DHA showed the back of an ambulance ripped out and metal debris strewn around it.
In a second accident, at least 16 people were killed after a truck driver hurtled into pedestrians in a town some 200 kilometers (120 miles) east, the health minister said.
The accident in Derik in Mardin province “occurred after the breaks gave out on a lorry, which hit a crowd,” Health Minister Fahrettin Koca said on Twitter.
A further 29 were injured, eight of them gravely, he said.
Turkish media shared footage of a driver losing control of his truck, then careening towards nearby vehicles and pedestrians trying to flee.
Turkey’s official Anadolu press agency said an accident involving three vehicles had happened at the same site shortly before, and emergency responders were already at the scene when the lorry drove into crowd.