A huge manhunt was underway across Europe last night for at least one jihadist feared to be still at large after plotting the Barcelona terrorist attacks.

Police and security services were hunting for the remaining members of a Moroccan-born terror cell, amid fears that they could be preparing further attacks at popular tourist areas.

Moussa Oukabir The 17-year-old key suspect of the Barcelona van outrage, Moussa Oukabir, was one of five terrorists shot dead by Spanish police during an attack on the coastal resort of Cambrils in the early hours of yesterday, authorities confirmed last night.

They also named Said Aalla, 18 and Mohamed Hychami, 24 as among those shot dead. Four other suspects were taken into custody.

But police were last night continuing to appeal for information on Younes Abouyaaqoub, 22. There were also reports that two further suspects were being sought.

A French security official said last night that Spanish police were looking for a Renault Kangoo van rented on Thursday in Spain by the suspects that may have crossed into France.

Security officials believe the attacks on Barcelona and Cambrils were the work of a terror cell of at least 12 people, who may have been inspired by the London Bridge outrage in June.

On Thursday afternoon, Oukabir and his associates drove a van along Barcelona’s crowded Las Ramblas thoroughfare, ploughing into tourists leaving 13 dead and more than 100 injured.

Among those thought to have been killed was a seven-year-old British boy, who had been visiting Barcelona for a family wedding. Julian Cadman, who was born in Tunbridge Wells, Kent, but later moved to Australia, had been strolling along Las Ramblas with his mother, Jumarie, when they were both mown down.

Mrs Cadman was last night understood to be still in hospital in an induced coma, unaware that her son was missing, feared dead. Her husband, Andrew Cadman, who had been unable to attend the Catalonian wedding and had stayed at home in Sydney, boarded a flight to Barcelona and was due to land late last night.

Among the other victims was an Italian tourist, Luca Rosso, who was hit as he walked through the streets with his fiancée. Another Italian, Bruno Gulotta, 35, a father of two, was also killed in front of his wife and children.

After carrying out the attack, Oukabir is believed to have fled on foot, before hijacking a Ford Focus car, stabbing the driver, and jumping a checkpoint, in order to make his escape. It is then believed he travelled to the coastal resort of Cambrils, where he met up with four fellow jihadists.

Driving an Audi A3, they travelled at speed along the town’s promenade but crashed and flipped the car.

The jihadists then got out of the vehicle and started to attack the terrified onlookers with knives and axes. All of the jihadists were shot dead by police who were on the scene as part of a heightened security operation following the Barcelona attack.

Despite his role as ringleader in the attacks it was not thought that Oukabir had been known previously to the security services. But social media accounts reputed to be linked to him contained a series of Islamist comments. In one post, when asked what he would do on his first day as absolute ruler of the world, Moussa replied: Kill all infidels and only allow Muslims to continue the religion.

His older brother, Driss, 28, was among four men in custody, who were being held on suspicion of involvement in the atrocities.

A huge explosion at a house in the town of Alcanar, 120 miles south of Barcelona, in which one man died, was connected with the attacks.

Police who searched the remains of the property discovered a large number of gas canisters which they believe were intended to be packed into a vehicle and driven into crowds. Police chief Josep Lluis Trapero said they were planning a much bigger atrocity than the one that took place.

Yesterday, Mariano Rajoy, the Spanish prime minister, King Felipe VI and Carles Puigdemont, the president of Catalonia where both attacks took place held a minute of silence in Barcelona. It was followed by the crowd shouting not afraid.