Now, it appears at least one NATO nation doesn’t feel the same way.
If Turkey follows through on its leader’s comments, what would it mean for Sweden, Finland and NATO? Here’s what we know so far.
Why is Turkey saying it’ll block Sweden and Finland’s NATO requests?
As Finland and Sweden inched closer to making a decision on NATO membership, Turkey hinted last week it would not view their applications positively, mainly citing those nations’ histories of hosting members of groups Turkey deems terrorists.
In a news conference on Monday, Erdogan said his nation would not approve their bids to join NATO, labelling Sweden a “hatchery” for terrorist organizations and adding it had terrorists in its parliament.
“How can we trust them?” he said.
Turkey has said Sweden and Finland harbour people it claims are linked to groups it deems terrorists, namely the Kurdistan Workers Party (PKK) militant group and followers of Fethullah Gulen, which Turkey accuses of orchestrating a 2016 coup attempt.
Turkish state broadcaster TRT Haber said on Monday that Sweden and Finland had not granted approval for the repatriation of 33 people that Turkey requested.
Swedish Foreign Minister Ann Linde said on Saturday that Sweden, just like the rest of the European Union, considered PKK a terrorist organization.
Erdogan also said Turkey would oppose NATO bids from those who imposed sanctions on it, and Sweden and Finland had slapped arms export embargoes on Turkey after its Syria incursion in 2019.
But while Turkey’s leader is projecting toughness, his spokesperson said on Saturday Turkey hasn’t shut the door to Sweden and Finland joining NATO as it wants negotiations and a clampdown on what it sees as terrorist activities.
“It’s not entirely surprising (Turkey is announcing its intention to block Sweden and Finland’s NATO bids) because the leader of Turkey … is a very tough and very tricky negotiator,” said Aurel Braun, a professor of international relations and political science at the University of Toronto.
“This would be an opening step in what could be some prolonged negotiating tactics.”
Can Turkey block Sweden and Finland's NATO membership?
Sweden and Finland need each of NATO‘s 30 members to approve their applications, so if one nation rejects their proposals then the deals would be dead, said Andrew Rasiulis, a defence expert with the Canadian Global Affairs Institute.
“There’s no wiggle room here. NATO ascension is by consensus, and that means everybody,” he told Global News.
“If Turkey refuses consensus … it’s done. There’s no ascension for Finland and Sweden.”
Russia’s invasion of Ukraine rattled Europe’s security structure and led Sweden and Finland to choose sides after staying out of the U.S.-led NATO alliance during the Cold War.
The decisions by the two Nordic nations to apply to NATO set them on a path toward ending policies of military non-alignment that had defined their defence strategies for decades.
“As far as expansion goes, including new members Finland and Sweden, Russia has no problems with these states, none,” Russian President Vladimir Putin said in response to the news this week.
He did, however, accuse the United States of using the enlargement in an “aggressive” way to aggravate an already difficult global security situation. He said Russia would respond if the alliance moves weapons or troops forward.
Diplomats have said Turkey would be under pressure to yield as Finland and Sweden would greatly strengthen NATO in the Baltic Sea.
“More than likely this will be resolved, but (Erdogan) is going to make it somewhat tougher to create some suspense,” Braun said.
“At the end of the day, Erdogan is going to have to make a decision on where do his highest interests lie? Is it in trying to extract extra concessions from Sweden and Finland and from NATO? Or is it better to be on NATO’s side? Especially since on the ground … Russia is losing the war it appears, and Erdogan would not want to be seen on the losing side.”
How likely is Turkey to block Finland and Sweden from joining NATO?
When Finland and Sweden were mulling the idea of submitting NATO membership requests, Secretary-General Jens Stoltenberg said they would be “warmly welcomed and I expect the process to go quickly.”
Canada has also expressed its support for the two nations, with Foreign Affairs Minister Melanie Joly saying Monday the country was in favour of a “quick” NATO accession for Sweden and Finland.
But with Turkey appearing ready to block their requests, it could be tougher for them to become members now, Rasiulis said.
Turkey could be using the opportunity to get Sweden and Finland to stop supporting what it deems as terrorist groups in the country, to potentially solidify a bid into the European Union that it has sought to do for years, and possibly get sanctions imposed on the country lifted, he explained.
“These are hard bargains,” Rasiulis said.
“These could be some tough negotiations here with no certainty of success.”
NATO and the United States have said they’re confident Turkey will not hold up membership of Finland and Sweden, which could take up to a year to cement.
Meanwhile, Finland and Sweden feel they can reach an agreement with Turkey, Finland’s president said on Tuesday.
“Statements from Turkey have very quickly changed and become harder during the last few days,” said President Sauli Niinisto said during an address to Sweden’s parliament.
“But I am sure that, with the help of constructive discussions, we will solve the situation.”
Niinisto said he talked with Erdogan a month ago, and the message then had been supportive of their NATO bids.
“But in the last week he has said ‘not favourable,’” Niinisto said. “That means we have to continue our discussions. I am optimistic.”
Global News reached out to Global Affairs Canada for comment on Turkey’s position, but did not receive a response by deadline.
— with files from Reuters