An accord signed with Finland and Sweden to lift Turkey's veto on their NATO membership bids is not the end of the matter and obliges the Nordic states to keep their promises, President Recep Tayyip Erdoğan was cited as saying on Friday.

After four hours of talks in Madrid on Tuesday, Erdoğan and his Finnish and Swedish counterparts agreed on a series of security measures in return for backing by Ankara, which had raised concerns about terrorism and arms embargoes.

Speaking to reporters on a flight back from the NATO summit in Madrid, Erdoğan said there was no need to rush ratifying the two bids in Parliament. Ankara should first see if they keep promises made under the memorandum, including on extraditing suspects sought by Turkey, he said.

"This should be known: These signatures don't mean the issue is done ... Without our Parliament's approval, this does not go into effect. So there is no need to rush," Erdoğan said.

"The ball is in their court now. Sweden and Finland are not NATO members currently. When there is any mistake, we already have undeniable documents and we will do what is necessary," he added.

Erdoğan said the decisions taken at Madrid will bear fruit in time.

"Promises that were made are of course important but the main point is the implementation," he said on the landmark memorandum signed between Finland, Sweden and Turkey.

With the signing of the memorandum, Turkey lifted an objection to the Nordic countries' NATO bid. In return, Finland and Sweden will address Turkey's terrorism concerns.

However, Erdoğan said Turkey will be cautious as "a country that has repeatedly been stabbed in the back in its fight against terrorism."

"We will closely monitor whether the promises made to our country are fulfilled in the coming period," he further said.

"From now on, it will be much more difficult for PKK and FETÖ members to make terrorist propaganda, attack our country and our citizens and vandalize," he said.

"Sweden will extradite 73 terrorists to us. They have sent 3-4 of them so far, but that is not enough. The Ministry of Justice and Ministry of Foreign Affairs, MİT (Turkish National Intelligence) will keep a firm grip on the issue," he added.

As a result of Turkey's efforts in Madrid, the PKK and its Syrian branch the YPG, and the Gülenist Terror Group (FETÖ) were written off as terrorist groups in NATO's records for the first time, he underlined.

Asked about the extradition of suspects, Erdoğan said if the Nordic countries did not send these individuals "then we will do what is necessary through our institutions and units."

In the backdrop of NATO's new security policy, Erdoğan said his country is maintaining a "balanced policy" in relations with Russia and Ukraine, as it does not want any harm to its "diplomatic traffic."

He said Turkey has ties with Russia and receives almost 40% of its natural gas from Russia.

"On the other hand, we are currently working on nuclear energy, Akkuyu Power Plant. The foundation for the fourth part will be laid in a few months, perhaps in July," he said.

Aside from energy, Turkey and Russia also cooperate in the defense industry, he said.

Erdoğan said a special session on terrorism and threats emerging from the south was held at the summit at Turkey's request.

He further stated that "in the (NATO) Strategic Concept, we marked for the first time that terrorist organizations threaten our security forces and our peoples and territories."

NATO leaders on Wednesday approved the 2022 Strategic Concept, a blueprint for the alliance for the next decade. It covers the alliance's priorities and goals for the next 10 years, and sets its joint position on emerging challenges, including Russia, while also addressing China for the first time.

The 2022 Strategic Concept accuses China of pursuing "coercive policies" that threaten NATO's "interests, security and values." It cites the "deepening strategic partnership" between China and Russia as a threat, saying that "their mutually reinforcing attempts to undercut the rules-based international order run counter to our values and interests."