The warning came a day after a storm swept through the neighbouring region of Catalonia, leaving 18 people injured, including one seriously.

National weather agency AEMET said its highest red alert would be in place for the coast of Valencia until midnight, warning of "extraordinary danger" and the risk of flash floods.

Earlier on Monday the agency downgraded its alert level for Catalonia a notch from its highest red level to orange, signalling a "significant risk of rain".

Videos circulating on social media showed torrents of mud carrying away cars and debris on Sunday in the region, as a storm swept through the region.

Catalonia's civil protection service said 17 people were lightly injured, and one seriously, due to the torrential rains.

Firefighters responded to dozens of calls from people trapped in vehicles or requiring assistance to remove fallen trees or debris from rockslides, it added.

In Santa Barbara, one of the hardest-hit towns, mayor Josep Lluis Gimeno described the damage caused by the storm as "historic", particularly to farms in the area.

"We can't even find the manhole covers. We can't find anything. Everything is uprooted," he told local radio.

Heavy rains forced the temporary closure of key roads and railway lines and led to university shutdowns.

The AP-7 highway along the Mediterranean coast reopened on Monday morning, but authorities reported severe traffic congestion, with one lane still closed in each direction.

Widespread flooding in Valencia in October 2024 killed more than 200 people in Spain's worst such disaster in decades.

Scientists say that a hotter atmosphere, which holds more water evaporating from the rapidly warming Mediterranean Sea, increases the risk and intensity of flooding from extreme rainfall in the region.