In a joint statement released on Wednesday, Chris Coons, and Mitch McConnell stressed that American security is strengthened by a robust NATO alliance.
The designation gives non-members of the North Atlantic Treaty Organisation access to military and financial advantages.
Turkey retains the option to delay the formal approval process.
The admission of Finland and Sweden to NATO will be a grave mistake with far-reaching consequences, says Russian Deputy Foreign Minister Sergei Ryabkov.
The Russian military officer claimed the U.S. had spent more than $5 billion on military biological programmes since 2005.
However, Russia has continued to claim that it has not suffered any significant losses.
Joseph Biden was sworn in as American president on January 20.
