This the 'person of interest' police are looking for
Eye witnesses reported hearing shots and "loud bangs" outside the T-Centralen train station, roughly a five minute walk from the scene of the truck crash – which has so far killed three people.
Police initially appeared to say they had made two arrests near the station, but have since back-tracked and it is feared the warped attacker is still at large and mingling among the crowds.
The metro has been closed and the station is in lockdown.
The huge truck ploughed into the Ahlens department store front leaving a trail of bloodied bodies on the floor.
Minutes later reports of gunfire began to emerge, flooding social media sites.
However, police have come out to retract a previous statement issued saying there was a confirmed active shooter in the Fridhemsplan area.
Shops on the street in Fridhemsplan have closed down and people are being locked inside.
Armed police have swooped on the stations in Stockholm
People were suddenly running from basement level screaming into the trains
Armed police are at the main railway station in Stockholm.
Daniel Szirányi who is currently locked inside a train carriage said armed police have rushed to the scene.
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He told Express.co.uk: “People were suddenly running from basement level screaming into the trains.
"We had to lay on the floor
Still sitting in the train.
“Not sure about the situation outside the locked train.
“Station area is emptied. Security forces/guards around.
"Everyone is quiet…shocked."
LIVE IMAGES: SWEDEN TERROR Fri, April 7, 2017
The vehicle drove into crowds on Drottninggatan (Queen Street) – one of the city's major pedestrian streets, just before 3pm local time, before crashing into Åhlens Mall
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Truck rams into crowds in central Stockholm
One woman wrote on Twitter: “Friend are trapped at the dentist at fridhemsplan. Police say it is anxious outside.”
Videos have begun to emerge of terrified people on a train in the central station crouching down and shouting out to have the doors locked.
Michael Jonsson terror researcher at the Swedish Defence Research Agency said: “If the first reports are accurate there are large similarities to the incidents in Berlin and in Nice.”
The Mall of Scandinavia has been evacuated, according to Swedish publication Expressen.
Stockholm terror: Truck drives into crowds as reports of shooter on the loose
Police in Stockholm: Masked officers are on scene – previous reports of shots fired
Police are urging people to stay away from the area and two people have been arrested.
At least two people have been detained by police -the first arrest was made at Olof Palmes gata and the other at Klara North Church Street.
Parliament has been cordoned off.
Unconfirmed reports claim three people are dead from the truck crash.
Swedish Prime Minister Stefan Löfven told a press conference: “Sweden has been attacked. Everything indicates this is an act of terror.”
The incidents in Sweden are at least a ten minute drive apart
Säpo Swedish Security police have confirmed at least two people are dead.
A statement said: “The Security Service received the alarm at 2:55pm on Friday that a truck driven into a crowd on Drottninggatan in Stockholm. Large number of people wounded.
“The Security Service is assisting the Police Department in the investigation that has now begun.”
A lorry crashed into shoppers in Sweden
Sapo added it was trying to identify the suspect or suspects behind the attack.