The North Atlantic Treaty Organization (NATO) formally invited Sweden and Finland to join the alliance on Wednesday after Turkey dropped its opposition to the move.

World leaders, including President Joe Biden, gathered in Madrid earlier in the week for the NATO Summit. Turkish President Recep Tayyip Erdogan met with Finland President Sauli Niinistö and Sweden Prime Minister Magdalena Andersson on Tuesday to hash out details of the two countries’ push to join NATO – a move that came after Russia invaded Ukraine and which Turkey originally said it would not support.

“In that meeting, the leaders agreed a trilateral memorandum to address Turkey’s legitimate security concerns, paving the way for Finland and Sweden’s NATO membership,” a NATO statement posted late Tuesday read.

NATO Secretary General Jens Stoltenberg oversaw the meeting and later praised the result. (RELATED: US Issues Warning To Russia As Finland, Sweden On Cusp Of Joining NATO)

“I strongly welcome the signing of this trilateral memorandum, and I strongly welcome the constructive approach all three countries have shown during the negotiations. Finnish and Swedish membership of NATO is good for Finland and Sweden, it is good for NATO, and it is good for European security,” Stoltenberg said.

NATO has now formally invited Sweden & Finland to join the military alliance, which would expand the membership from 30 to 32. “Today, we have decided to invite Finland & Sweden to become members.” Secretary General Jens Stoltenberg expects ratification process to move quickly.

— Kaitlan Collins (@kaitlancollins) June 29, 2022

The official invitation paves the way for the alliance to bolster up to 32 member nations.

The trilateral agreement between Turkey, Finland and Sweden includes an extradition request for 33 terror suspects in the two Nordic countries, according to CNN. The agreement also addresses concerns from Turkey “around arms exports, and the fight against terrorism,” according to Stoltenberg.

“We [Turkey] will ask them to fulfill the requirements of our applications after this memorandum of understanding,” Turkish Justice Prime Minister Bekir Bozdag told reporters shortly after the news, according to CNN. “We have already applied for extradition. The files of six PKK and six FETO terrorists in Finland and 10 FETO and 11 PKK terrorists in Sweden.”

“Our ministry will write about their return and remind them again … Once again, we ask them to fulfill their promises,” Bozdag added.

Support in Finland and Sweden for joining NATO skyrocketed after Russia’s invasion in February, according to Business Insider. Should the deal officially go through, Russia’s border with NATO countries would more than double.

Turkey’s reversal is a major loss to Russian President Vladimir Putin, who has vehemently opposed increasing NATO and vowed to retaliate in May after Finland announced its intention to seek membership.