The Turkish president Tayyip Erdoan agreed on Monday to send to parliament Sweden’s application to join NATO. This appears to have ended months of drama surrounding a matter that has caused tension within the alliance as the war in Ukraine has continued.

In response to Russia’s invasion of Ukraine, Sweden and Finland both applied for NATO membership in the past year. They abandoned their policy of non-alignment which had endured through decades of Cold War.

Sweden’s NATO application has yet to be approved by Turkey or Hungary. Stockholm is working to get Sweden accepted at the NATO summit, which starts on Tuesday in Vilnius.

Jens Stoltenberg, NATO Secretary General, said at a press conference that he was “glad to announce” that President Erdogan had agreed to send the accession protocol to Sweden as quickly as possible to the grand assembly and to work closely with them to ensure its ratification. He called it a “historical” step.

On the eve before the summit, he had held several hours of discussions with both Erdogan and the Swedish Prime Minister Ulf Kritersson in an attempt to break the deadlock.

Erdogan has been holding out for several months. He said that Sweden’s entry into the alliance hinged on implementing a deal struck last year at the summit of the alliance in Madrid, and that Ankara would not compromise.

Sweden has been accused by Turkey of not doing enough to combat people it views as terrorists. This includes members of the banned Kurdistan Workers Party, which is a terrorist organization in Turkey, the EU, and the United States.

Erdogan and Kristersson seemed relaxed before the meeting. The Swedish leader joked about parking his aircraft next to the larger Turkish aircraft at Vilnius Airport.

Kristersson, a Swedish journalist, told reporters that the statement made on Monday was “a big step” towards the final ratification by Sweden of its NATO membership.

Both countries issued a statement in which they said that Sweden reiterated its commitment to not support Kurdish groups, and to actively support efforts made by Turkey to re-energize the EU accession process.

Erdogan said on Monday that the European Union must open the door for Ankara to join before the Turkish parliament approves Sweden’s application to join NATO.

Stoltenberg stated that Erdogan had agreed to have the ratification happen “as quickly as possible” in parliament, but could not provide a calendar. The Turkish parliament took two weeks to ratify Finland.

The Turkish government’s approval of Sweden’s NATO application would be the final hurdle to overcome for Sweden’s accession. All members must approve applications before they can join NATO.

Since months, the United States and its NATO allies have been trying to put pressure on Ankara. NATO partners think that Turkey has used its membership in Sweden to press Washington to purchase the F-16 fighters from Lockheed Martin Corp. (LMT.N), which it requested to buy for $20 billion and 80 modernization kits to upgrade its existing warplanes.

The U.S. president Joe Biden will meet Erdogan face-to-face during the summit.

John Irish, William Maclean, Rosalba o’Brien, and Rosalba o’Brien edited the article. Additional reporting was done by Niklas pollard, Andrius sytas, Justyna pawlak, Anna Ringstrom, Johan Ahlander, in Stockholm and Ezgi Erkoyun, in Istanbul.