US President Joe Biden and top officials from his administration repeated that they are confident Ankara's objection would not be a roadblock for the accession process of the Nordic countries, even though they did not spell out how Turkey's position could be changed.
Finland and Sweden formally applied on Wednesday to join US-led NATO, a decision spurred by Russia's invasion of Ukraine, with the accession process expected to take only a few weeks despite Turkey's objections.
Ankara says Sweden and Finland harbour people linked to groups it deems terrorists, namely the Kurdistan Workers Party (PKK) militant group and followers of Fethullah Gulen, whom Turkey accuses of orchestrating a coup attempt in 2016.
"We have such a sensitivity as protecting our borders from attacks by terrorists organisations," Erdogan told MPs from his ruling AK Party in parliament.
Erdogan said NATO allies had never supported Turkey in its fight against Kurdish militant groups, including the Syrian Kurdish YPG, which Ankara also views as a terrorist group closely tied to the PKK.
"NATO expansion is only meaningful for us in proportion to the respect that will be shown to our sensitivities," he said.
Biden's national security adviser Jake Sullivan in a briefing said he believed Finland and Sweden at the end of the day would have an "effective and efficient" accession process. He said Turkey's concerns "can be addressed".
Turkish Foreign Minister Mevlut Cavusoglu, on a visit to the United States, also said he conveyed to his US Secretary of State Antony Blinken in a meeting in New York that Ankara had "legitimate security concerns" that needed to be addressed.
"They (Blinken) said they will convey the necessary messages about overcoming Turkey's concerns," he said.
The meeting was "positive, constructive", a US State Department official said.
When asked about Turkey's objection, Biden told reporters: "I'm not going to Turkey, but I think we're gonna be OK."
Biden will host the leaders of Sweden and Finland at the White House on Thursday to discuss their NATO applications.
Turkish state broadcaster TRT Haber said on Monday Sweden and Finland had not granted approval for the repatriation of 33 people that Turkey requested.
"So you won't give us back terrorists but you ask us for NATO membership? NATO is an entity for security, an organisation for security. Therefore, we cannot say yes to this security organisation being deprived of security," Erdogan said.
Erdogan has also said Turkey would oppose the NATO bids from those who imposed sanctions on Ankara. Sweden and Finland had banned arms exports to Turkey after its Syria incursion against the YPG in 2019.
