Swedish police
Swedish police [Representational Image]Reuters

The suspect of Sweden's Stockholm truck attack on Tuesday confessed to committing a "terrorist crime" which killed four people and injured dozens.

Rakhmat Akilov, a 39-year-old native of Uzbekistan, admitted to committing a terror crime, his lawyer Johan Eriksson said in a court in Stockholm. The prosecutors in the case have asked the court to remand Akilov in police custody.

Akilov was the prime suspect of driving a rented truck into pedestrians on a busy street in central Stockholm last week. At least 15 people were injured in the incident.

Swedish authorities arrested the suspect on Friday after police released images taken from CCTV footage. The suspect was dressed in a hooded jacket. Another man was also arrested for links with the Uzbek man. The head of the National Police, Dan Eliasson, said that the suspect had been known to police.

National Police Commissioner Dan Eliasson said that police had also discovered a suspect device inside the truck which was driven into the department store, stating that the technical device was found in the driver's seat.

The police commissioner said that they do not know what the device is, but they do know that it should not have been in the truck.

"Seven people have been brought in for questioning as a result of these events," Jonas Hysing, national head of police operations, told public broadcaster SVT, after several raids were conducted across Stockholm over the weekend.

Swedish Prime Minister Stefan Lofven has described the incident as a terrorist attack, and asked for tightening of borders.

"Terrorists want us to be afraid, want us to change our behaviour, want us to not live our lives normally, but that is what we're going to do. So, terrorists can never defeat Sweden, never," Lofven said.