Up to 364 millimetres (14 inches) of rain lashed parts of the provincial capital Jinan between midnight and 5 am, according to state broadcaster CCTV.

The downpours triggered flash floods in two villages in the town of Dawangzhuang, "destroying or damaging" 19 homes, CCTV said.

"At present, all-out efforts are being made to search for and recover the missing persons," the broadcaster said.

It added that authorities would "carry out post-disaster rescue and follow-up work in an orderly manner".

Natural disasters are common in China, particularly in summer when some regions experience heavy rainfall while others bake in searing heat waves.

China is the world's biggest emitter of the greenhouse gases that scientists generally agree cause climate change and make extreme weather more frequent and intense.

But it is also a global renewable energy powerhouse that aims to make its massive economy carbon-neutral by 2060.

Six people were killed and more than 80,000 evacuated due to floods in southern Guizhou province in June, according to state media.

A landslide on a highway in Sichuan province this month also killed five people after it swept several cars down a mountainside.