If Sweden and Finland will be NATO members, they need to first take Turkey's concerns into consideration, President Recep Tayyip Erdoğan said Tuesday.

Addressing reporters in the capital Ankara ahead of his trip to the critical NATO Madrid summit where he will meet the leaders of the Nordic nations and NATO, Erdoğan said that Turkey does not want empty words, but rather concrete results from these countries.

"NATO membership comes with responsibilities. If Sweden and Finland are to become members of NATO, they have to take into account the security concerns of Turkey, a member of the alliance for 70 years," he said.

"We will hold a quadripartite meeting (on Sweden and Finland's membership bids) and see what point they have reached. We do not want dry words, we want results. We are sick of passing the ball around in the mid-field. As of now, they are producing words," Erdoğan said.

He added that Ankara expects Stockholm and Helsinki to prevent the terrorist PKK and all other offshoots from operating freely in their countries.

Erdoğan also stated that he spoke to United States President Joe Biden earlier in the day and added that Biden wants to meet with him on the sidelines of the NATO summit in Madrid.

"We spoke with Mr. Biden this morning and he expressed his desire to get together tonight or tomorrow. We said it was possible," he told reporters.

Later in the day, the White House confirmed the planned meeting and added that leaders at the Madrid summit will also take "historic decisions to strengthen the alliance's collective defense and security."

Erdoğan reiterated Ankara's criticism of NATO allies, particularly the U.S., for their support of the PKK terrorist group's Syrian branch YPG.

"We expect from our allies not to discriminate between NATO members, and that threat against one should be interpreted as a threat against all," the president said adding that he would explain Turkey's position to allies at the summit and in bilateral meetings.

The PKK is a designated terrorist organization in the U.S., Turkey and the European Union, and Washington's support for its Syrian affiliate has been a major strain on bilateral relations with Ankara. The U.S. primarily partnered with the YPG in northeastern Syria in its fight against the Daesh terrorist group. On the other hand, Turkey strongly opposed the YPG's presence in northern Syria. Ankara has long objected to the U.S.' support for the YPG, a group that poses a threat to Turkey and that terrorizes local people, destroying their homes and forcing them to flee.

Under the pretext of fighting Daesh, the U.S. has provided military training and given truckloads of military support to the YPG, despite its NATO ally's security concerns. Underlining that one cannot support one terrorist group to defeat another, Turkey conducted its own counterterrorism operations, over the course of which it has managed to remove a significant number of terrorists from the region.

Erdoğan signaled over the weekend that no progress had been made in Sweden's bid to join NATO, urging Stockholm to take "concrete actions" to meet Ankara's concerns.

He also said Monday after the Cabinet meeting that Turkey "will provide documents and images demonstrating our interlocutors' hypocrisy" toward groups Ankara views as terrorists.

Erdoğan also said he will do "whatever is necessary for our country’s rights and interests" at the NATO summit in Spain.

"We will tell them clearly that it is not possible to expect a different attitude from Turkey unless this picture changes," he added.

Breaking with decades of a policy of neutrality, Sweden, along with Finland, formally applied to join NATO last month, a decision spurred by Russia's war on Ukraine that began on Feb. 24. But Turkey, a longstanding member of the alliance, has voiced objections to the membership bids, criticizing the countries for tolerating and even supporting certain terrorist groups such as the PKK, the YPG and the Gülenist Terrorist Group (FETÖ).

Ankara called on Stockholm and Helsinki to prevent the terrorist group from collecting funds, recruiting new members, and ensuring that it ends its activities and propaganda against Turkey, which has also called on Sweden and Finland to lift arms embargoes imposed against itself in 2019 over Ankara's military operation in Syria.

Turkey said documents it received from Sweden and NATO in response to the earlier written demands it presented the two candidates were far from meeting its expectations and any negotiations must first address Turkish concerns.

While the two Nordic countries said talks to resolve the dispute would continue, Erdoğan said that Ankara had not received any responses to its demands, including stopping support for terrorist groups, lifting arms embargoes on Ankara and extraditing terrorism suspects it seeks.

Any NATO membership requires the approval of all 30 members of the alliance. Turkey has been a NATO ally for more than 70 years and has the alliance's second-biggest army.

Turkish officials said they do not consider the NATO summit as a final deadline for resolving its objections to Finland and Sweden joining the Western defense alliance.

Madrid Summit

NATO leaders are set to meet in Madrid to discuss what could be its largest military deployment since the end of the Cold War. The summit will run from Tuesday to Thursday, with talks expected to center on NATO's response to the war in Ukraine, and the Finnish and Swedish petitions to join the 30-member military alliance.

NATO's chief on Monday said they aim to "make progress" on Finland and Sweden's membership bids ahead of the Madrid summit.

"We also aim to make progress on Finland and Sweden's historic applications for NATO membership, while ensuring the security concerns of all allies are addressed," NATO Secretary-General Jens Stoltenberg told a pre-summit press conference in Brussels.

Stoltenberg said NATO needs to take into account the concerns expressed by allies, in this case by Turkey, explaining, "And that's the reason also why we have intensified the dialogue with our ally and with Finland, Sweden over the last weeks."

The NATO chief said the leaders of Finland and Sweden will meet with Erdoğan in Madrid on Tuesday for a four-way meeting, which he will also participate in. Stoltenberg added that this meeting will be preceded by another meeting between senior officials from all three countries at the NATO headquarters on Monday.

But Turkey said the four-way meeting did not mean that Ankara was close to lifting its objection to the two Nordic countries joining the military bloc.

"Our NATO summit in Madrid will be transformative with many important decisions, including on the new strategic concept for a new security reality," Stoltenberg said.

Stoltenberg said NATO would "transform the NATO Response Force and increase the number of our high readiness forces to well over 300,000."

Finnish President Sauli Niinisto also said on Tuesday there was now somewhat more mutual understanding between Finland and Turkey ahead of the NATO summit in Madrid.

He added that he was neither optimistic nor pessimistic when it comes to the outcome of the ongoing negotiations over Finnish NATO membership.

"The general view is that the discussions went somewhat better, which should mean that understanding has somewhat increased on both sides," Niinisto told reporters, referring to talks between diplomats ahead of his meeting with Erdoğan, scheduled for later on Tuesday.

Negotiations aimed at overcoming Turkey's objection to Sweden's bid to join NATO have made progress and a breakthrough could come at the alliance's current summit in Madrid, Swedish Foreign Minister Ann Linde also said on Tuesday.

"We are prepared for the eventuality that something positive could happen today, but it might also take longer," Linde told daily Svenska Dagbladet (SvD).

"In that case, we will stay patient and continue discussions even after the summit."