Swedish police suspect the powerful explosion that ripped through two apartment buildings, injuring dozens in the city of Linkoping on Friday morning, was the result of a deliberate act.

In a press conference later in the day, police investigator Magnus Skoglund said the blast, which damaged 109 apartments, was caused by 'an explosive device deliberately placed outside'.

He said while police were investigating a 'working hypothesis' it was too early to say what the device was and who put it there.

The explosion has blown out windows and destroyed balconies in the buildings in central Linkoping

In an interview with public broadcaster SVT Skoglund said police suspected members of the criminal underworld could be behind the blast - but it was too early to say with certainty which group was responsible.

Police did confirm there was no information to suggest the blast was terror-related.

The device detonation at around 7am sparked a large emergency response and saw bomb squads, a police helicopter and dozens of ambulances rush to the scene in the Hamngatan/Ågatan area.

There were no reported casualties but it's believed dozens received minor injuries in the blast and the local hospital had initiated a disaster response.

Kim Berg, a spokesman for the region's hospitals, said two people remain hospitalised in stable condition. Victims mainly suffered cuts from splintered and flying glass or had been treated for shock.

Police said a bomb squad had been deployed to the area after Friday's blast. People can be seen milling outside the damaged buildings

The explosion blew out windows and destroyed balconies in the buildings in central Linkoping, about 175 kilometers (110 miles) southwest of Stockholm. One of the buildings had five floors, while the other had four floors.

The cause of the blast wasn't immediately known, but police had not ruled out the possibility it might be the result of a criminal act.

It's believed the explosion happened outside the apartments - but it's unclear at this stage where exactly.

Several people spoke to Swedish media outlet, Aftonbladet in the immediate aftermath of the blast.

Witness Pontus Johansson lived opposite the house where the explosion happened.

'I was standing in the shower and noticed that it was shaking...It rumbled, like thunder, though more sharp.

'It's pretty much chaos, and quite a lot of police here outside.'

Jonas Lassmark's grandmother Brigitta lives in an apartment nearby. He described scenes of absolute chaos.

'She was really scared, called my dad and so I had to run here. I would say that she lives about 100 meters [330 feet] from where it slammed.

'All the windows are broken in her apartment... There is [debris] in her bed.'

The force of the blast that hit on Friday morning also blew out windows in the surrounding shops

Gösta Sundin, 85, lives on the ground floor of the house where the explosion occurred.

He told Aftonbladet he was quite concerned at the time of the blast, but things had settled down since so he was feeling a bit calmer.

'The whole house shook. I went out and then a lot of ambulances arrived.

'The police blocked off [the area] around the house and said not to stay outside, so I went into my apartment again.'

He said the glass panes were completely destroyed at the hairdressing salon and the driving school near the affected house.

The explosion has blown out windows and destroyed balconies in the buildings in central Linkoping about 110 miles southwest of Stockholm

Ambulance and fire crew arrive at the scene of the explosion in the southern Swedish city. Local media reported at least 20 ambulances attended the call in the immediate aftermath of the blast

Photos being shared on social media show two multi-storey buildings with shattered windows and wrecked balconies, with some damage to their roofs also visible.

Police said in a statement that several blocks around the area had been cordoned off but that there were no plans to evacuate residents.

While the cause of the explosion was not clear, Sweden has seen several cases in recent years where explosives were used in suspected gang-related attacks.

Police said in a statement that several blocks around the area had been cordoned off but that there were no plans to evacuate residents