Turkey agreed on Tuesday to lift opposition to Sweden and Finland joining NATO, ending a deadlock at the NATO summit in Madrid as the war in Ukraine sparked Europe’s worst security crisis in decades.

“We have now reached an agreement that paves the way for Finland and Sweden to join NATO,” NATO Secretary-General Jens Stoltenberg said after high-level emergency talks with the three countries’ leaders. He remarked it as a “historic decision”.

Among its many shocking consequences, President Vladimir Putin’s invasion of Ukraine prompted Sweden and Finland to renounce their longstanding non-aligned status and apply to join NATO to protect them from increasingly aggressive and unpredictable Russian influence – the border with Finland is very long. Under the NATO treaty, an attack on any member would be considered an attack on all and trigger a military response across the alliance.

NATO operates by consensus, with Turkish President Recep Tayyip Erdogan threatening to stop the Nordic pair, insisting they have changed their stance against the Kurdish insurgent group that Turkey considers terrorists.
On Tuesday, after weeks of diplomacy and hours of talks, Finnish President Sauli Niinistö said the three leaders had signed a joint agreement to break the deadlock.

Turkey said it has got what it wants, including full cooperation in fighting the rebel group. The leaders of the 30-nation coalition will formally invite both countries to join on Wednesday, Stoltenberg said. All individual countries must approve the decision, but he said he believed Finland and Sweden would become members, which could happen within a few months.

Swedish Prime Minister Magdalena Anderson said the deal was “good for Finland and Sweden. Good for NATO”. The membership process should be completed “as soon as possible”, she said.

“But with 30 committees approving this, you never know,” Anderson told The Associated Press. Turkey hailed Tuesday’s deal as a victory, saying the Nordic countries had agreed to crack down on groups Ankara sees as a threat to national security, including the Kurdistan Workers’ Party (PKK) and its expansion in Syria. They also agreed to “not impose embargo restrictions on Turkey’s defence industry” and “take concrete measures against the extradition of terrorists,” the statement said.

Turkey has asked Finland and Sweden to extradite wanted criminals and lifted arms restrictions imposed after Turkey’s 2019 military invasion of northeastern Syria.

Turkey, in turn, agreed to support the invitations of Finland and Sweden to become NATO members at the 2022 Madrid summit.

US President Joe Biden congratulated the three countries for taking a crucial step. Amid speculation that the US will play a role in ending the standoff, a senior administration official said Washington had offered no concessions to Turkey to accept the deal. But the official said the US played a crucial role in helping bring the two parties closer, and Biden spoke with Erdogan at the request of Sweden and Finland on Tuesday morning to help encourage talks.