A roundabout was also closed off after a live hand grenade was found by a member of the public.
The national bomb squad was called to Ystad and confirmed the object was ready to detonate.
Police spokesperson Kim Hild said: “The bomb squad confirmed it was a grenade.”
The officer added that the object was found by highway E65 – which goes through numerous European countries.
Duty officer Hans Nilsson said: “At 12:57 we received the call about the dangerous item from a private individual.
“The first patrol arrived at the scene and estimated that the bomb group had to be called in.”
“The national bomb squad have secured it. The hand grenade was sharp so the person who called it in did right to alert us.
“Currently we do not know how it got there.”
Just hours earlier a police station was evacuated after two hand grenades were handed in at the reception.
The entire building was evacuated and the bomb squad was dispatched from Stockholm to evaluate the situation.
According to police the “objects were being treated as if they were live”.
Police spokeswoman Tove Hägg said: “[The hand grenades] are being treated as if they are active until they have been thoroughly investigated.
“We do not know who submitted them but they were submitted to the reception.”
The bomb squad have now said the hand grenades were not loaded – but the situation with the second police station, which was evacuated because of a dynamite scare, is still unclear.
In Sollentuna, near Stockholm, police were evacuated at lunchtime due to the dynamite being handed in at the reception.
Only parts of the station were evacuated but they will remain shut off until the bomb technicians make an assessment, a police spokesman said.