President Joe Biden on Thursday welcomed the leaders of Sweden and Finland to the White House, as he hailed the applications of the once-neutral countries to join the North Atlantic Treaty Organization in response toRussia's invasion of Ukraine.

Biden greeted Prime Minister Magdalena Andersson of Sweden and President Sauli Niinistö of Finland at the White House with handshakes and laughter as they met for trilateral conversations on the NATO mutual defense pact as well as broader European security concerns.

“having two new NATO members in the high north will enhance the security of our alliance.” Biden said after escorting his fellow leaders to the Rose Garden.

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 Feb. 24.