When President Joe Biden sits down with Sweden's prime minister on Wednesday -- just a week before the annual NATO summit -- he will be sending a message to allies and adversaries alike.

To Turkey and Hungary -- two NATO allies who have yet to green-light Sweden's accession to NATO -- Biden will be demonstrating the unwavering nature of the US' commitment to Sweden joining the alliance, administration officials said. And to adversaries like Russia, administration officials hope to send another strong signal support for strengthening the military partnership with Sweden, regardless of its status as a NATO member country.

Biden's meeting with Swedish Prime Minister Ulf Kristersson was intentionally scheduled a week before the president is set to participate in the NATO summit in Vilnius, Lithuania, where officials say Biden intends to spotlight the alliance's strengthened defense posture on its eastern flank and the expansion of NATO, with Finland becoming the alliance's most recent member.

White House officials once hoped that Sweden would be approved to join the alliance by the time of the summit, a demonstration of the alliance's newfound strength following Russia's invasion of Ukraine.

Now, US officials do not expect Sweden's membership to be approved in time for the NATO summit next week and hope that Biden's meeting with the Swedish prime minister demonstrates the US's commitment to achieving that end.

NATO formally invited Sweden and Finland to join the alliance at last year's summit in Madrid as the two nations were inspired to join the pact by Russia's invasion of Ukraine. Finland officially became the 31st member of the alliance in April, adding 830 miles to the alliance's frontier with Russia.

However, Sweden's formal acceptance has been held up.

NATO has an open-door policy, meaning that any country can be invited to join if it expresses an interest, as long as it is able and willing to uphold the principles of the alliance's founding treaty. However, under the accession rules, any member state can veto a new country from joining.

An overwhelming majority of NATO members welcomed Finland and Sweden's applications, but two countries -- Turkey and Hungary -- began to stall the process. Those nations dropped their objections to Finland, but Sweden's application has been blocked over Turkish claims that Sweden allows members of recognized Kurdish terror groups to operate in Sweden, most notably the militant Kurdistan Workers' Party (PKK).