The two Nordic countries, previously neutral, applied to join in the wake of Russia’s invasion of Ukraine.
President Biden met the leaders of the two countries at the White House and hailed them as “two close, highly capable partners”.
“They meet every NATO requirement and then some,” he said. “Having two new NATO members in the high north will enhance the security of our alliance.”
Russian President Vladimir Putin has demanded the alliance stop expanding toward Russia’s borders.
Several NATO allies, led by the United States and Britain, have signalled they stand ready to provide security support to Finland and Sweden should the Kremlin try to provoke or destabilise them during the time it takes to become full members.
While neutral throughout the Cold War, Finland and Sweden now cooperate closely with NATO.
The countries will only benefit from NATO’s Article 5 security guarantee — the part of the alliance’s founding treaty that pledges that any attack on one member would be considered an attack on them all — once the membership ratification process is concluded.
Public opinion in Finland and Sweden has shifted massively in favor of membership since Russia invaded Ukraine on February 24.
Each of NATO’s 30 member countries has the power to veto a membership bid and Turkish President Recep Tayyip Erdogan said he remains opposed to the two countries joining the alliance.
Asked whether he was confident the two countries would be able to join the alliance, the President said: “I think we’re going to be okay.”
US National Security Adviser Jake Sullivan said Finland and Sweden were “working directly” with Turkey to address its concerns and the US are also speaking with Turkish officials to “try to help facilitate” a resolution.