At least 24 people were killed in southern China's Guangdong province Wednesday when part of a highway collapsed due to heavy rain.

Guangdong, a densely populated industrial powerhouse, has been lashed by rainstorms in recent weeks, causing severe flooding and landslides in some areas.

The downpours have been much heavier than would normally be expected for the time of year and have been linked to accelerating climate change.

State news agency Xinhua said that a stretch of road between Meizhou city and Dabu county in Guangdong province caved in at around 2:10 a.m. on Wednesday (6:10 p.m. GMT Tuesday).

The incident caused 20 vehicles to become trapped and involved a total of 54 people, according to Xinhua.

As of 3 p.m. (7 a.m. GMT), "24 people have been confirmed dead, and 30 are receiving all-out emergency care in hospital," Xinhua said.

Recovery work was ongoing and the lives of those hospitalized were "not currently at risk," it added, without specifying their injuries.

An aerial photograph published by state broadcaster CCTV showed wrecked vehicles lying in a deep muddy pit where the highway once ran.

Dozens of emergency vehicles and cranes congregated along the intact section of the road, which bisects a steep, wooded slope.

Videos circulating on social media – apparently filmed before dawn – showed flames and smoke emanating from the pit.

"You can't go any further," a man is heard saying in one video, adding that parts of the road had given way.

CCTV said the collapse was a "natural geological disaster ... (that occurred) under the impact of persistent heavy rain."

It reported that a nearly 18-meter (59-foot) stretch of road had fallen away.

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.