Sweden inched a step closer to joining NATO on Monday after Turkey's president sent accession protocols to parliament.

Russia's invasion of Ukraine prompted both Sweden and Finland to seek NATO membership but the former's entry had been stymied by Turkey.

Turkish President Recep Tayyip Erdogan's sign off on the accession protocols comes after months of delays but it is unclear how long the process will take.

Erdogan's proposal must make its way out of a parliamentary commission and then be opened up for a general vote on the main floor of the assembly where the Turkish president and his allies have the majority needed to ratify Sweden's bid.

Finland, which applied for membership in May 2022 along with Sweden, joined NATO in April 2023.

Erdogan accused Sweden of being too lenient on militant groups, most notably the militant Kurdistan Workers' Party (PKK), and harboring people associated with a 2016 Turkish coup attempt.

Turkish officials have also accused Swedish officials of being complicit in Islamophobic demonstrations, such as the burning of the Quran.

Since applying for membership, Sweden has tightened its anti-terror legislation and agreed to work more closely with Turkey on its security concerns.

In July, NATO chief Jens Stoltenberg announced that Erdogan had agreed to send the accession protocols to Turkey's parliament for ratification, but did not specify a time frame. The announcement represented a stunning about-face for Erdogan, who had previously suggested Sweden could only join the alliance after Turkey was accepted into the European Union.

The United States welcomed the news that Erdogan had signed and sent Sweden's NATO accession protocols to the Turkish parliament on Monday.

"Obviously we have been calling for ratification of Sweden accession for some time," State Department spokesperson Matt Miller said.

"We look forward to that bill being considered in the Turkish parliament and passed as soon as possible," he said at a department briefing.

Erdogan's actions represent a step forward in Sweden's quest to join NATO but does not mean that Sweden will immediately become the next member of the alliance.

Hungary also has not voted to approve Sweden's membership. In September, Hungary's Prime Minister said the country was in no rush to approve Sweden's bid, according to Reuters.