She made the remarks at the joint press conference with Armenian counterpart Edward Nalbandian in Yerevan.
The Sweden FM said it is necessary to do everything to prevent the escalation of the situation.
According to her, there is a need to make every effort to find a solution to the conflict within the framework of the OSCE Minsk Group.
"We call on the parties to the conflict to work for a peaceful settlement of the conflict", Wallström added.
The Swedish FM will visit Baku today as part of her visit to the South Caucasus.