The death toll from a collapsed highway in southeastern China climbed to 48 on Thursday as searchers dug for a second day through a treacherous and mountainous area.

One side of the four-lane highway in the city of Meizhou gave way about 2 a.m. on Wednesday after a month of heavy rains in Guangdong province. Twenty-three vehicles fell down a steep slope, some sending up flames as they caught fire. Construction cranes were used to lift out the burnt-out and mutilated vehicles.

Officials in Meizhou said three other people were unidentified, pending DNA testing. It wasn’t immediately clear if they had died, which would bring the death toll to 51. Another 30 people had non-life-threatening injuries.

The search was still ongoing, Meizhou city Mayor Wang Hui said at a late-afternoon news conference. No foreigners have been found among the victims, he said.

Search work has been hampered by rain and land and gravel sliding down the slope. The disaster left a curving earth-colored gash in the otherwise verdant forest landscape. Excavators dug out a wider area on the slope.

“Because some of the vehicles involved caught fire, the difficulty of the rescue operation has increased,” said Wen Yongdeng, the Communist Party secretary for the Meizhou emergency management bureau.

“Most of the vehicles were buried in soil during the collapse, with a large volume of soil covering them,” he said.

He added that the prolonged heavy rainfall has saturated soil in the area, “making it prone to secondary disasters during the rescue process.”

Over 56 centimeters (22 inches) of rain has fallen in the past four weeks in the county where the roadway collapsed, more than four times as much as last year. Some villages in Meizhou flooded in early April, and the city has seen more rain in recent days.

Parts of Guangdong province have seen record rains and flooding in the past two weeks, as well as hail. A tornado killed five people in Guangzhou, the provincial capital, during rain and hail storms last weekend.

The highway section collapsed on the first day of a five-day May Day holiday, when many Chinese are traveling at home and abroad.

Chinese leader Xi Jinping said that all of China’s regions should improve their monitoring and early warning measures and investigate any risks to ensure the safety of the public and social stability, state broadcaster CCTV said.

(AP)