Finland and Sweden dropped decades-long policies of military non-alignment and applied to join the western alliance last May in the wake of Moscow's offensive in Ukraine.

"We have many times expressed regret over Finland and Sweden's move toward membership and said many times that Russia does not pose a threat to these countries," Kremlin spokesman Dmitry Peskov said.

"We do not have any dispute with these countries... They have never posed any threat to us and, logically, we did not threaten them," Peskov said.

Turkish President Recep Tayyip Erdogan has suspended negotiations with Sweden but looks ready to ratify Finland's membership.

Finnish President Sauli Niinisto said Turkey had reached a decision on ratifying his country's NATO bid and said he will visit Istanbul this week to hear it from Erdogan.

Turkey and Hungary are the only countries that have yet to ratify the countries' applications, which must be accepted by all 30 existing members of the alliance.

Russia sees NATO enlargement as an existential threat to its security and has used Ukraine's wish to join the alliance to justify the offensive.