Four people were killed and dozens are still missing after rainstorms buffeted southwestern China last week, state media reported Wednesday.

Severe downpours hit Jinyang, a mountainous county in Sichuan province, on August 21, but the extent of the damage was not immediately reported.

Over a week after the rains, state broadcaster CCTV said Wednesday the storms triggered floods that struck a steel processing site where more than 200 people were working.

"At present, the floods have caused four deaths and left 48 people missing, and rescue work is ongoing," CCTV reported.

It added that five people had been detained on suspicion of "failing to report or falsely reporting a safety incident".

President Xi Jinping ordered officials to "do all they can to search for the missing people... and comfort their families", CCTV said.

The incident "should be completely investigated and the responsible parties dealt with according to law", Xi reportedly said.

China has seen a string of disasters caused by extreme weather in recent months.

At least 78 people died when Typhoon Doksuri brought record-breaking rains across northern China last month, authorities have said.

Scientists say human-caused global warming is exacerbating extreme weather events, making them both more likely and more deadly.