A manhunt is underway in Spain as police search for the driver of a van that plowed into pedestrians on Barcelona’s busiest boulevard Thursday, leaving at least 13 people dead and more than 100 injured.

The perpetrator was seen escaping on foot after deliberately driving into crowds of people on Las Ramblas, at around 5:30 p.m. local time, in what police suspect was one of a number of planned attacks.

So far three men have been arrested as country-wide anti-terror operations are underway.

Islamic State has claimed responsibility for the attack though the claim has not been verified.

Five men suspected of attempting to carry out a related attack were shot by police early Friday morning in the nearby town of Cambrils. The attackers, who were wearing explosives, were intercepted after driving a car into a crowd of people, injuring six civilians and one police officer. Catalan officials have since suggested that the explosives were fakes.

One person was also killed in an explosion in a property in a separate town southwest of Barcelona. Police sources say the residence was being used for preparing explosive devices.

Three men are currently in police custody following the attacks.

Police have named the first as Driss Oukabir, a 28-year-old Moroccan man who is thought to have hired the rental van used in the Barcelona attack. However, police in Ripoll, the Catalonian town where he was living and arrested late Thursday, said he was not the driver of the van.

The other two men, one from Spain’s north African enclave of Melilla, have not yet been named, though neither is currently thought to be the driver of the van.

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It is still not clear how many people were involved in the various attacks.

At least 13 people were killed and more than 100 injured when a hired white Fiat van was used to zigzag at an estimated 50 miles per hour along Barcelona’s pedestrianized Las Ramblas boulevard.

The vehicle sped for at least 500 meters into crowds walking along the popular tree-lined strip, before crashing into a newspaper kiosk. The assailant was then seen escaping from the vehicle on foot.

Police quickly confirmed the incident as a terror attack.

It marks the latest in a series of attacks using vehicles to bring carnage to the streets of Europe in the past 13 months, however, it is the first time Spain has been targeted in 13 years. In 2004, 192 people were killed and 2,000 injured in a series of train bombings.

Citizens from 24 countries are said to be among the victims of Thursday’s attack.

Among them are people from France, Germany, Belgium, the Netherlands, Australia, America and Hong Kong.

The youngest among the dead is believed to be a three-year-old girl, who died shortly after being taken into hospital.

This story is developing. Please check back for further updates.

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