In the wake of Finland's leaders announcing their determination to join, the Kremlin said it represented a hostile move that threatened Russia, warning vaguely of "retaliatory steps, both of a military-technical and other nature".
Sweden has been rebuilding its military over the last decade, particularly since Russia's annexation of Crimea from Ukraine in 2014, buying U.S.-made Patriot air defence missile systems and basing troops on the Baltic island of Gotland.
A cross-party parliamentary review on Friday said joining NATO would boost Sweden's national security and help stabilise the Nordic and Baltic regions.
(Reporting by Niklas Pollard, Simon Johnson and Johan Ahlander Editing by Frank Jack Daniel, David Clarke, Peter Graff)