"Our strong desire in Finland has been and still is to join NATO together with Sweden," Foreign Minister Pekka Haavisto told reporters in Helsinki, adding: "our position remains the same."

Ankara has refused to ratify the two countries' NATO membership bids, primarily because of Sweden's refusal to extradite dozens of suspects that Ankara links to outlawed Kurdish fighters and a failed 2016 coup attempt.

Sweden has a bigger Kurdish diaspora than Finland and a more serious dispute with Ankara.

Ankara has also reacted with fury to a decision by the Swedish police to allow a protest at which a far-right extremist burned a copy of the Koran outside the Turkish embassy in Stockholm earlier this month.

It has also been outraged by a Swedish prosecutor's decision not to press charges against a pro-Kurdish group that hung an effigy of Erdogan by its ankles outside Stockholm City Court.

Erdogan on Sunday drew a clear distinction between the positions taken by Sweden and Finland in the past few months.

"If necessary, we can give a different response concerning Finland. Sweden will be shocked when we give a different response for Finland," Erdogan said.

But Haavisto, who said he held talks with his Turkish counterpart following Erdogan's remarks, rejected that option.

"Sweden is our closest ally in defence and foreign policy", he said.

"I still see the NATO summit in Vilnius in July as an important milestone when I hope that both countries will be accepted as NATO members at the latest."