In response to Russia's invasion of Ukraine, Sweden and Finland applied last year to join NATO but faced unexpected objections from Turkey
Finland may become the next member of NATO as Erdogan signals Turkey will ratify the Scandinavian country's bid.
The long-delayed process got underway in a debate about the bid in Hungary's parliament.
Hungary has accused the countries of spreading falsehoods about the health of democracy in Hungary.
An anti-NATO could represent a paradigm shift away from traditional military alliances and towards a more holistic and collaborative approach to global security in a multipolar world.
The United States Secretary of State will approach the meeting with multiple prongs; one focused on earthquake relief and the other focused on Finland's bid to join NATO.
Finland has been urged to move forward with NATO without confirmation of Sweden's involvement.
Swedish Prime Minister Ulf Kristersson said his country continued to abide by a trilateral agreement on NATO accession signed last year between Sweden, Finland and Turkey.
"Our position on Finland is positive, but it is not positive on Sweden," Erdogan said.
Sweden and Finland wanted to join NATO when Russia invaded Ukraine, but Turkey has been blocking the request.