Several found dead in flood-hit areas after torrential rains slam Spain

An unspecified number of bodies were found in areas hit by flash flooding in southeastern Spain, the leader of the Valencia region told reporters early on Wednesday.

This came after torrential rains caused by a cold front moving across southeastern Spain flooded roads and towns on Tuesday, prompting authorities in the worst-hit areas to advise citizens to stay at home and avoid all non-essential travel.

"Dead bodies have been found, but out of respect for the families, we are not going to provide any further data," said the regional leader of Valencia Carlos Mazon.

Spain's weather agency AEMET declared a red alert in the eastern Valencia region, with some areas such as Turis and Utiel recording 200 millimetres of rainfall.

Meanwhile, emergency services workers backed by drones were looking for six people who were missing in the wake of the flash floods in the town of Letur in the eastern province of Albacete, the central government's representative in Castilla-La Mancha, Milagros Tolon said.

Dozens of videos shared on social media appeared to show people trapped in floodwaters, several of them hanging on to trees to avoid being swept away.

Other footage showed firefighters using long-line rescue helicopters to help people caught in floodwaters. A viral video appeared to capture a tornado, a relatively rare phenomenon in Spain.

Radio and TV stations were receiving hundreds of calls for help from citizens trapped in flooded areas or searching for loved ones, as emergency services were unable to reach all affected locations.

"If (emergency services) have not arrived, it's not due to a lack of means or predisposition, but a problem of access," Mazon said, adding that reaching certain areas was "absolutely impossible".

Footage showed firefighters rescuing trapped drivers amid heavy rain in the Valencian town of Alzira and flooded streets with stuck cars.

Scientists say extreme weather events are becoming more frequent due to climate change. Meteorologists believe the warming of the Mediterranean, which increases water evaporation, plays a key role in making torrential rains more severe.

Schools and other essential services were suspended in the worst-hit areas.

Local emergency services requested the help of UME, a military unit specialised in rescue operations, in the area of Utiel-Requena, where farmers' association ASAJA said the storm was causing significant damage to crops.