Swedish police arrest suspected driver in lorry attack

Swedish police say they believe they have arrested the suspected driver of a lorry attack in the centre of that killed four peopley.

"The person in question has been arrested as the culprit ... in this case the driver," police spokesman Lars Bystrom said on Saturday.

"Then, there can be other people who are associated with him, but we do not know that at the current time."

The man was in custody in a northern Stockholm suburb on Friday and was later arrested on suspicion of having committed a terrorism crime.

Police have found explosives in the lorry used in the attack in Stockholm, Swedish television said on Saturday citing multiple unnamed police sources.

A picture of a man wearing a white sweater and dark hoodie under a military green jacket, with dark stubble on his face, was being circulated by Swedish police. 

"Sweden has been attacked. All indications are that it is an act of terrorism. Our thoughts are with the victims, their families and those injured," Swedish Prime Minister Stefan Löfven said in a statement.

"The Government is being kept up-to-date and is doing everything it can to assist the relevant authorities in their work. I encourage everyone to be vigilant and to pay attention to the information from the police."

Body-like forms covered by blankets were seen on Drottninggatan in central Stockholm where the lorry rammed the Ahlens department store, a Reuters witness said.

Following the attack, the Sweedish national rail company announced that all trains to and from Stockholm Central Station had been cancelled for the rest of the day. 

An area of central Stockholm was cordoned off, and large numbers of police and emergency services were at the scene.

Translation: Sweden has been attacked. All indications are that it is an act of terrorism. Be vigilant, and listen to the Police information.

"I saw at least three dead, but probably more," Swedish radio reporter Martin Svenningsen said.

One witness identified only as Dimitris told the Aftonbladet daily that the lorry came "out of nowhere".

"I couldn't see if anyone was driving but it was out of control. I saw at least two people get run down. I ran as fast as I could away from there," he said.

Another shopper, 66-year-old Leander Nordling, was at Ahlens when he suddenly heard a loud bang.

"It sounded like a bomb exploding and smoke starting pouring in through the main entrance," he told daily Aftonbladet.

He and fellow shoppers took refuge in a supply closet inside the department store.

"After that the building was evacuated. There were a lot of guards who took care of us outside and they urged us to leave the scene immediately," Nordling said.

A spokeswoman for transport company Spendrups told AFP that the lorry "had been stolen during a delivery to a restaurant".

Police could not confirm the information.

"Police received a call from SOS Alarm that a person in a vehicle has injured other people on Drottninggatan," police wrote on Twitter.

Swedish police issued a warning for people to avoid the city centre.  

Though police are yet to confirm the motive behind the attack, European politicians have begun to react to the tragedy.

European Commission President Jean-Claude Juncker said the incident was "an attack on us all" and that Sweden "can count on the European Commission" for support.

"One of Europe's most vibrant and colourful cities appears to have been struck by those wishing it – and our very way of life – harm," he added.

German Chancellor Angela Merkel said in a tweet: "Our thoughts go out to the people in Stockholm, to the injured, their relatives, rescuers and police. We stand together against terror".

Norway police announced that airport police will be carrying weapons "until further notice" due to the attack in Stockholm.

On Friday, a fifth victim died after an attack last month in London in which Khalid Masood, a 52-year-old convert to Islam known to British security services, drove a car at high speed into pedestrians on London's Westminster Bridge before launching a frenzied knife assault on a policeman guarding the parliament building. 

The Islamic State group claimed an attack in Nice, France, last July, when a lorry killed 86 people celebrating Bastillle Day, and one in Berlin in December, when a lorry smashed through a Christmas market, killing 12 people.