Police in the Swedish capital of Stockholm have arrested a second person after a truck crash left at least four people dead.
The hijacked truck ploughed into pedestrians in a Stockholm street before ramming into a department store on Friday, killing four bystanders and injuring at least 15 others.
Police have already detained a suspect in relation to the crash, which the Swedish Prime Minister says is likely to have been an act of terrorism.
Later, police detained a second man said to be connected to the lethal truck attack, according to Swedish public broadcaster SVT, citing police sources.
SVT reports that the man was arrested in the Stockholm suburb of Hjulsta, and he is said to be linked to the man who was arrested earlier on Friday.
The horrific attack took place around 2.55pm local time on Friday when the truck rammed into the crowd in a pedestrian area in the capital known as Drottninggatan.
Nine of the 15 people injured were seriously hurt, Swedish emergency services have said.
"Sweden has been attacked," Swedish Prime Minister Stefan Lofven said just after the attack, according to The Huffington Post UK. "Everything points to a terrorist attack."
The Department of Foreign Affairs and Trade said no Australians were harmed in the attack.
"The Australian Embassy in Stockholm continues to liaise with local authorities to determine whether any Australians have been affected bya truck ramming incident in central Stockholm," DFAT told The Huffington Post Australia.
"The Department of Foreign Affairs and Trade is providing consular assistance to one Australian who was in the vicinity of the incident but was physically unharmed."
In Paris, the Eiffel Tower has had its lights turned off in a symbol of solidarity with Stockholm.
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