“They got away with certain goods which they loaded into another car,” said Towe Hägg at the Stockholm police district control centre.
The security truck is owned and operated by Securitas. The two guards were not physically harmed, reported Åke Andersson, head of information at Securitas, to TT.
The guards are being taken care of by crisis experts at the company.
“We have routines for this sort of thing which, unfortunately, we have to use all too often,” said Åke Andersson.
Police immediately began the hunt for the robbers and within an hour, according to Towe Hägg, one of the suspects was arrested in the Skyttbrink industrial estate in Botkyrka.
She said that a witness had called police after seeing cars on fire in the area.
After the robbery, metal spikes were found strewn across the E4 and it was closed off at Hallunda.
The robbers appear to have used explosives to get into the vehicle and what is thought to be a mask was found at the scene.
Earlier on Monday a outlet of the Swedish Cashier Service (Svensk Kassaservice) in Skogås was robbed. Three armed and masked men stormed in and threatened staff.
Nobody was injured but it is unclear how much they managed to steal.