southern China's Guangdong province on Wednesday, state media reported.
State broadcaster CCTV said a stretch of road between Meizhou city and Dabu county in Guangdong province caved in at around 2:10 am (1810 GMT).
The incident caused 18 vehicles to become trapped and involved a total of 49 people, CCTV said.
As of 11:45 am, «19 people have been confirmed dead, and 30 are receiving all-out emergency care in hospital», according to the broadcaster.
It added that the lives of those hospitalised were «not currently at risk» but did not specify their injuries.
Social media footage shared by local news outlets showed flames and smoke emanating from a deep, dark pit into which cars seemed to have plummeted.
Other clips showed around half a dozen people standing on a roadside gazing at the flashing lights of emergency vehicles in the distance.
Authorities have dispatched around 500 people to the site to help with the rescue operation, CCTV reported.
They are drawn from departments handling public security, emergency response, firefighting and mining rescue, according to the broadcaster.
Local authorities said in a notice that part of the S12 highway was closed in both directions and ordered drivers to take detours.
The cause of the collapse was not initially specified.
Guangdong has been hit by a string of extreme weather events in recent weeks, from fatal floods to a deadly tornado.