Turkey "got what it wanted" from Sweden and Finland before backing their drives to join NATO, Ankara said on Tuesday after agreeing to lift its opposition to the countries joining the defense alliance, ending an impasse that had clouded a leaders’ summit opening in Madrid amid Europe’s worst security crisis in decades, triggered by the war in Ukraine.

"Turkey has made significant gains in the fight against terrorist organizations," President Recep Tayyip Erdoğan's office said in a statement following the decision, adding: "Turkey got what it wanted."

The two Nordic countries have agreed to "cooperate fully with Turkey in its fight against the PKK" and other related terrorist groups, according to the statement.

They have also agreed to lift their embargoes on weapons deliveries to Turkey, which were imposed in response to Ankara's 2019 military operation into Syria.

The two countries will ban "fundraising and recruitment activities" of PKK-linked militants and "prevent terrorist propaganda against Turkey," Erdoğan's office said.

The PKK has been waging a decadeslong insurgency against the Turkish state that has claimed tens of thousands of lives.

The PKK is designated as a terrorist organization by Ankara and most of its Western allies. But the terrorist group's Syrian offshoot, the YPG, has been an important player in the United States-led international alliance against the Daesh terror group in Syria.

Sweden and Finland had historically declined to seek Nato membership, partly because of mixed public opinion and caution around their security relationship with Russia. But that dramatically changed after Russia launched an unprovoked attack on Ukraine in February, prompting both countries to ask to join.

It means the Swedish and Finnish leaders will be able to attend the Nato summit on Wednesday and Thursday as invitees, meaning that their countries are on a firm path to full membership, subject only to ratification by member states. That is considered a technical step.

Turkey had said it would block the applications of Sweden and Finland unless it received satisfactory assurances that the Nordic countries were willing to address what it regards as support for terrorist organizations, in particular, the PKK and its branches.

Finland and Sweden signed a trilateral memorandum with Turkey on Tuesday, pledging to address Ankara's concerns over their stance toward the PKK and the Gülenist Terror Group (FETÖ) to pave the way for their NATO membership. The following are the commitments that have been made by the Nordic countries:

1 - Finland and Sweden will not provide support to the YPG and FETÖ, and Turkey in return will extend its full support to the countries against threats to their national security. Finland and Sweden have agreed to reject and condemn terrorism in all its forms and manifestations, in the strongest terms. The countries will unambiguously condemn all terrorist organizations perpetrating attacks against Turkey, demonstrating their deepest solidarity with Turkey and the families of the victims.

2 - Finland and Sweden committed to confirming that the PKK is a proscribed terrorist organization and have pledged to prevent the group's activities and all other terrorist entities and their extensions, as well as activities by individuals in affiliated and inspired groups or networks linked to these terrorist organizations. Turkey, Finland and Sweden have agreed to step up cooperation to prevent the activities of these terrorist groups and the Nordic countries have agreed to reject the groups' goals.

3 - In addition to this, Finland underlined several recent amendments to its criminal code that expanded the scope of punishable terrorist crimes, the latest of which went into force on Jan. 1, 2022. At the same time, public incitement related to terrorist offenses was criminalized as a separate offense. Sweden, for its part, has confirmed that it will enter a new, tougher terrorist offenses act into force on July 1, and that the government is preparing to further tighten counterterrorism legislation.

4 - Turkey, Finland and Sweden have confirmed there are no longer national arms embargoes in place between them. Sweden is changing its national regulatory framework for arms exports in relation to NATO allies. In the future, defense exports from Finland and Sweden will be conducted in line with alliance solidarity and in accordance with the letter and spirit of Article 3 of the Washington Treaty.

5 - Turkey, Finland and Sweden committed to the following concrete steps:

The three countries have agreed to establish a joint, structured dialogue and cooperation mechanism at all levels of government, including between law enforcement and intelligence agencies, to enhance cooperation on counterterrorism, organized crime and other common challenges as they so decide.

Finland and Sweden will fight against terrorism with determination, resolve and in accordance with the provisions of the relevant NATO documents and policies, pledging to take all required steps to tighten further domestic legislation to this end.

Finland and Sweden will address Turkey's pending deportation or extradition requests of terror suspects expeditiously and thoroughly, taking into account information, evidence and intelligence provided by Ankara. The Nordic countries will establish necessary bilateral legal frameworks for security cooperation with Turkey, in accordance with the European Convention on Extradition.

Finland and Sweden will investigate and interdict any financing and recruitment activities of the PKK and all other terrorist organizations and their extensions, as well affiliates or inspired groups or networks.

Turkey, Finland and Sweden have committed to fighting disinformation and preventing their domestic laws from being abused for the benefit or promotion of terrorist organizations, including through activities that incite violence against Turkey.

Finland and Sweden will ensure that their respective national regulatory frameworks for arms exports enable new commitments to allies and reflect their status as NATO members.

6 - For the implementation of these steps, Turkey, Finland and Sweden will establish a permanent joint mechanism, with the participation of experts from the Foreign Affairs, Interior and Justice Ministries as well as intelligence services and security institutions. The mechanism will be open for others to join.

7 - Turkey also confirmed its longstanding support for NATO's open-door policy, agreeing to support the invitation of Finland and Sweden to become members of NATO at the 2022 Madrid summit.

After urgent top-level talks with the leaders of the three countries, NATO Secretary-General Jens Stoltenberg said: "I'm pleased to announce that we now have an agreement that paves the way for Finland and Sweden to join NATO. Turkey, Finland and Sweden have signed a memorandum that addresses Turkey's concerns, including around arms exports, and the fight against terrorism." He called it "a historic decision."

Among its many shattering consequences, President Vladimir Putin’s invasion of Ukraine has prompted Sweden and Finland to abandon their long-held nonaligned status and apply to join NATO as protection against an increasingly aggressive and unpredictable Russia – which shares a long border with Finland. Under NATO treaties, an attack on any member would be considered an attack against all and trigger a military response by the entire alliance.

After weeks of diplomacy and hours of talks on Tuesday, Finnish President Sauli Niinisto said the three leaders had signed a joint agreement to break the logjam.

Stoltenberg said leaders of the 30-nation alliance will issue a formal invitation to the two countries to join on Wednesday. The decision has to be ratified by all individual nations, but he said he was "absolutely confident" Finland and Sweden would become members, something that could happen within months.

Finland and Sweden also welcomed the agreement following the four-way talks.

Swedish Prime Minister Magdalena Andersson said the agreement was "good for Finland and Sweden. And it’s good for NATO."

She said completing the process of membership should be done "the sooner the better."

Asked if the Swedish public will see the agreement as a concession on issues like extraditions of PKK-linked militants regarded by Ankara as terrorists, Andersson said "they will see that this is good for the security of Sweden."

Noting that this agreement is valuable for the Swedish people, Andersson said: "I think it is good that we reached this agreement for the safety of Sweden and the Swedish people."

"Taking the next step toward a full NATO membership is of course important for Sweden and Finland. But it's also a very important step for NATO, because our countries will be security providers within NATO," Andersson also told Agence France-Presse (AFP) in an interview.

"I think this is an agreement that I can stand fully behind," she said.

Andersson said she had been able to lay out to President Erdoğan the changes in Sweden's terrorism legislation set to come into force next month.

"And of course, we will continue our fight against terrorism and as NATO members also do so with closer cooperation with Turkey," the Swedish premier said.

For his part, Niinisto said on Twitter: "Our joint memorandum underscores the commitment of Finland, Sweden and Turkey to extend their full support against threats to each other's security. Us becoming NATO Allies will further strengthen this commitment."

Noting that Finland takes Turkey's concerns "seriously," he said: "Finland condemns terrorism in all its forms and manifestations. As a NATO member, Finland will commit fully to the counterterrorism documents and policies of NATO."

"I am delighted to conclude this stage on Finland's road to NATO membership. I now look forward to fruitful conversations on Finland's role in NATO with our future Allies here in Madrid," he added.

However, Niinisto told reporters after the meeting that the trilateral memorandum does not list individuals for extradition but rather describes principles for extraditions related to terrorism, not individual citizens.

U.S. President Joe Biden congratulated the three nations on taking a "crucial step."

Amid speculation about a U.S. role in ending the deadlock, a senior administration official said Washington did not offer any concessions to Turkey to coax it to accept a deal. But the official said the U.S. played a crucial role in helping bring the two parties closer together, and Biden spoke with Erdoğan Tuesday morning at the behest of Sweden and Finland to help encourage the talks.

The agreement came at the opening of a crucial summit, dominated by Russia’s invasion of Ukraine, that will set the course of the alliance for the coming years. The summit was kicking off with a leaders' dinner hosted by Spain's King Felipe VI at the 18th-century Royal Palace of Madrid.

The agendas of the meetings Wednesday and Thursday are focused on strengthening defenses against Russia and supporting Ukraine.

Moscow’s invasion on Feb. 24 shook European security and brought shelling of cities and bloody ground battles back to the continent. NATO, which had begun to turn its focus to terrorism and other non-state threats, has had to confront an adversarial Russia once again.