Along with a number of well-known world leaders, Carlsson recently appealed for both sides to come together to negotiate peace.
"I'm, of course, very happy that this step has been taken," says Carlsson to Radio Sweden. "This is how it has to start if there's going to be a positive result. At the same time, we have to remember that this is just the first step, and there are several more hard steps to go before we come to a situation where we want to be."
The PKK has been waging a nearly 30-year battle against the Turkish government, seeking autonomy and greater rights.
Ocalan called for the withdrawal of thousands of his fighters from Turkey on Thursday.
The fight has killed tens of thousands of people, and the group is considered a terror organization by Turkey and its Western allies, including the United States, reports the Associated Press.
However, Ingvar Carlsson thinks that the group's terror classification could be lifted in the years to come.