This is an extension of an already extant policy.
Some interesting quotes from Swedish government sources though...
"The decision is based on the government's assessment that there is a threat to public order and internal security in Sweden,” a government press release stated."
Interior Minister Mikael Damberg indicated that the Swedish measures would not be necessary if there was a united European approach to border security.
"Sweden is one of a handful of countries that continue to have internal border controls due to lack of border controls at the Schengen's external borders," he said.
Looks like the quest to become an "humantitarian superpower" isn't going as well as they hoped. Unless you call a huge increase in violent crime including rape, and the emergence of a fascist political party to a position where they hold the balance of power a success. Who'd have thought that opening up your borders to as even more Muslim "refugees" (as a percentage of population) than Germany wouldn't work out well?
No, impossible for a progressive to forecast that. Even though I can remember saying so at the time, you guys, as always knew better. So compassionate, you warmed everyone's hearts, you did. Another triumph for wokedom.
Sadly for Sweden this demographic disaster is irreversible. Too late to shut the borders now, the damage is already done.