Spanish rescuers are focusing their search for missing people on underground garages and a multi-storey car park following last week’s devastating floods in Valencia.

It is feared shoppers and workers were trapped inside the car park at a shopping mall in Aldaia on the outskirts of Valencia, as floodwater deluged the area.

Police have confirmed that no victims were located in the first 50 vehicles inspected at the site.

But reports suggest these vehicles were found near the entrance to the car park, and much of the rest of it is still submerged and yet to be explored.

It comes as Spain’s State Meteorological Agency (AEMET) placed part of the north-eastern Catalonia region on red alert for torrential rain, with its capital Barcelona experiencing flooding on Monday morning.

Catalan media showed footage of cars partially submerged on a highway and floodwater entering a bus. Water has also entered parts of the city’s El Prat airport including the public area of Terminal 1 and more than 60 flights have been cancelled, delayed or diverted. Rail services have been suspended.

The death toll after a year’s worth of rain fell in parts of the region last week now stands at 217.

They include a missing British couple in their 70s, whose family confirmed they had been found dead in their car days after the flash floods hit the region.

On Monday morning Spain’s interior minister refused to place a number on those still missing.

The storm caught many victims in their vehicles on roads and in underground spaces such as car parks, tunnels and garages where rescue operations are particularly difficult.

Outside the Bonaire shopping mall in Aldaia on Monday, rotting piles of debris lined the roads while noisy generators pumped out water – but thousands of gallons remain inside the mall car park.

When the BBC asked a local police officer how much longer the operation would take, he said he could not give an estimate, but that teams would stay here as long as necessary.

As is the case in many parts of the region that have been crushed by the floods, there is a vacuum of information.

There has been anger at a perceived lack of warning and insufficient support from authorities after the floods.

On Sunday, the king and queen of Spain were pelted with mud and other objects by angry protesters during a visit to the town of Paiporta – one of the worst-affected in Valencia.

Objects were also thrown at Prime Minister Pedro Sánchez, who was quickly evacuated.

The Civil Guard has opened an investigation into the chaotic scenes, Interior Minister Fernando Grande-Marlaska told public broadcaster TVE.

He blamed “marginal groups” for instigating the violence where mud spattered the monarchs’ face and clothes.

Local authorities in Valencia have extended travel restrictions for another two days to facilitate the work of the emergency services, cancelled school classes and urged people to work from home.

Meanwhile Spain’s defence minister has announced that a further 2,500 soldiers will join the 5,000 troops already sent to the region over the weekend to help distribute food and water, clean up streets and guard against looters.

A warship carrying 104 marine infantry soldiers as well as trucks with food and water is also on its way to Valencia’s port.