The ‘lightly injured’ suspect was arrested in Marsta, a suburb north of Stockholm, after members of the public contacted police to say he was acting strangely.
A police spokesman said: ‘One person has been arrested who may be connected with the incident.’
The hijacked vehicle crashed into a packed shopping centre and burst into flames. Three men jumped out from inside and opened fire before trying to stab pedestrians, witnesses said.
Two men were tackled to the ground and arrested but a third suspect went on the loose.
Police released CCTV of the man wearing a green jacket, white shoes and a grey hoodie. Police have confirmed the suspect arrested in Marsta resembles the man in the photos they released earlier.
Officers said the vehicle crashed into a group of people on the street outside a shopping centre in Klarabergsgatan after racing down six streets at about 3pm local time.
Hundreds of shoppers were seen fleeing for their lives after the articulated lorry rammed into the corner of the building.
Horrifying images of the aftermath showed blood smeared on the roads and bodies covered by blankets. Police said 15 people were injured.
Stockholm Police said they were questioning the two men arrested in the immediate aftermath of the attack but they are not currently suspected of criminal activity.
A police spokesman said: ‘I can confirm that we have taken in two people for questioning, but that does not necessary means that they are suspects.’
Following the lorry crash, armed terrorists were seen running into Stockholm’s Central railway station and opening fire. Two people were also said to have been stabbed.
Spendrups Brewery said the truck belonged to its company and was stolen.
The truck’s driver, who has not been named, was hurt in the hijacking after trying to cling to the vehicle.
He had climbed out of the cab while delivering its cargo of beer. At least one man, wearing a balaclava, took the chance to climb in and drove off, knocking the victim over as he tried to get back on board. He was injured, but not seriously.
The terror attack came weeks after the Westminster Bridge killer Khalid Masood used a car to murder five people before stabbing a policeman to death outside Parliament.
Last year, ISIS terrorists used trucks to kill dozens in Berlin and Nice.
After yet another terror attack on European soil, MailOnline understands:
- Terror suspect jumped into cab of a beer lorry while its driver was making a delivery
- Masked man sped through central Stockholm aiming at pedestrians before crashing into the Åhlens department store Klarabergsgatan. At least four people are dead and 15 injured
- Witnesses heard shots fired and two suspects were filed being arrested in the street
- Police have confirmed a third suspect has been arrested and admitted responsibility for the attack
- Stockholm’s main railway station was shut down
- The tube network was also closed amid fears fugitive is hiding underground but is now open
- Horrifying images show streets smeared with blood and bodies covered in blankets
- Prime Minister Stefan Lofven says the truck crash ‘is an act of terror’ and urges public to clear the streets