Barcelona terror: Sydney schoolboy missing after deadly attack that killed 14

A Sydney schoolboy is missing in Barcelona following the deadly terror attack that killed 14 and injured more than 100, when a vehicle ploughed into pedestrians.

Seven News understands the seven-year-old boy, Julian Cadman, was visiting Barcelona with family to attend a wedding.

His mother Jumarie or "Jom" for short, is in hospital, in an induced coma. Her husband is flying to Barcelona tonight to search for their son.

A white Fiat van sped for one kilometre along the popular Las Ramblas pedestrian strip about 4.30pm on Thursday before crashing into a newspaper kiosk.

Australian schoolboy Julian Cadman is believed to be missing in Barcelona following the deadly terror attack. Picture: Supplied
Australian schoolboy Julian Cadman is believed to be missing in Barcelona following the deadly terror attack. Picture: Supplied

As security forces hunted for the van's driver, who was seen escaping on foot, police said they had killed five attackers on Thursday night in Cambrils, a town south of Barcelona, to thwart a separate attack using explosive belts.

Six civilians and a police officer were injured in Cambrils when the attackers ran them over in a car, before police shot them dead and carried out controlled explosions. Police said the Cambrils incident was linked to the van attack in Barcelona.

Before the van plowed into the tree-lined walkway of Las Ramblas, one person was killed in an explosion in a house in a separate town southwest of Barcelona, police said. Residents there were preparing explosives, a police source added.

The van reportedly used in the attack.
The van reportedly used in the attack.

Two NSW women remain in serious but stable conditions in hospital, while two Victorian men - both of whom were hit by the attacker's van - have been discharged after receiving treatment.

Little Julian's family has taken to Facebook to plead for his safe return, after he became separated from his mother during the attack.

"My Grandson, Julian Alessandro Cadman is missing. Please like and share," Tony Cadman wrote on Facebook Friday afternoon.

"We have found Jom [my daughter in law] and she is serious but stable condition in hospital."

Witnesses said there were horrific screams as the vehicle drove through the crowds. Photo: AAP
Witnesses said there were horrific screams as the vehicle drove through the crowds. Photo: AAP

Foreign Minister Julie Bishop confirmed one Australian is missing and four others have been injured in a terror attack in Barcelona.

There are no reports any Australians were involved in two connected attacks in the Spanish towns of Cambrils and Alcanar, both south of Barcelona.

Police said they had arrested a Moroccan and a man from Spain's north African enclave of Melilla, though neither was the van driver. A third man was arrested in the town of Ripoll on Friday in connection with the attack.

Islamic State has claimed responsibility for the attack.

"We are concerned, but we are working closely with authorities to determine the whereabouts of the one Australian unaccounted for," Ms Bishop told reporters in Melbourne on Friday.

"We condemn in the strongest possible terms these brutal and cowardly attacks, and in the case of Las Ramblas, clearly designed to harm and affect tourists who were visiting the area," Ms Bishop said.

More than 100 people were injured after the terror attack. Photo: AAP
More than 100 people were injured after the terror attack. Photo: AAP

"The Australian government remains committed to ensuring that Australians are as safe as they can be, either overseas or here in Australia."

Among the injured were three Dutch tourists and authorities said one of the dead was from Belgium.

Las Ramblas, a street of stalls and shops that cuts through the center of Barcelona, is one of the city's top tourist destinations.

Australia's consular hotline has received more than 380 calls, with government advice updated to urge travellers to exercise caution and heed the directions of local authorities.

There are 2000 Australians registered with the embassy as being in Spain, and roughly 20,000 Australians in Spain at any one time.