The Turkish parliament's foreign affairs commission delayed a vote on Sweden's NATO membership bid on Thursday in a further setback to the Nordic country's hopes of joining the Western alliance after 18 months of waiting.

Chairman Fuat Oktay said the commission, which is controlled by President Tayyip Erdogan's ruling party, will hold further talks and may bring the bill back on its agenda next week - but he did not set a clear timeline.

"For all of our lawmakers to approve Sweden's NATO membership, they need to be fully convinced. We will discuss all of these in our (next) commission meeting (on the issue)," Oktay told reporters after hours of debate.

The commission can pass bills by a simple majority. It may invite the Swedish ambassador to brief lawmakers if needed and if parliament's regulations allow, Oktay added.

Erdogan said this month he would try to facilitate the ratification process, but added Sweden had not taken enough action on Kurdish militants.

For ratification, the bill needs to be approved by the commission before being put to a full parliament vote, which could come days or weeks later. Erdogan would then sign it into law to conclude the process, the length of which has frustrated Ankara's allies and tested its Western ties.

Sweden and Finland requested to join NATO in May last year following Russia's invasion of Ukraine.

Erdogan raised objections at the time to both requests over what he said was the Nordic nations' protection of those Turkey deems terrorists, as well as their defence trade embargoes. Turkey endorsed Finland's bid in April but has kept Sweden waiting.

Turkey has demanded that Sweden take more steps to rein in local members of the Kurdistan Workers' party (PKK), considered a terrorist group by the European Union and United States.

In response, Stockholm introduced a new anti-terrorism bill that makes membership of a terrorist organisation illegal, while also lifting arms export restrictions on Turkey. It says that it has upheld its part of a deal signed last year.

LAWMAKERS NOT CONVINCED

Despite comments by Turkish Deputy Foreign Minister Burak Akcapar outlining the measures taken by Sweden, lawmakers from both the ruling AK Party and opposition voiced reservations and, in a rare move, delayed the vote.

"I value NATO's enlargement. However, we must remove some of the controversies in our minds. Sweden has become a safe haven, or a heaven, for some terrorist organisations," said Ali Sahin, a lawmaker from the AK Party.

"We find the steps Sweden has taken until now valuable, but we don't find them sufficient," he added.

NATO members Finland, Canada and Netherlands also took steps to relax arms-export policies towards Turkey during the process, while the White House said it would move ahead with the transfer of F-16 fighter jets to Turkey in consultation with the U.S. Congress.

While there is no clear timeframe on approving the purchase request for the F-16s, Ankara has linked the issue to Sweden's bid. On Thursday, Oktay repeated Erdogan's view that "if they have a Congress, we have a parliament".

Some analysts say Turkey's parliament could fully ratify the bid by a NATO foreign ministers meeting in Brussels on Nov. 28-29.

A senior U.S. State Department official, speaking on the condition of anonymity, said Turkey was "very interested" in finalising the ratification before the NATO meeting in Brussels though it was ultimately Ankara's call.

"Now, it's up to them whether their system will produce the consent in that timeframe, but we're continuing to speak with them about that," the official said.

While the Biden administration has not linked the ratification with the sale of F-16 jets, members of Congress have made it clear they're unlikely to approve that sale until Turkey ratifies the Nordic country's NATO bid, the official said.

"As the administration, we're trying to keep both ends ready to move in a timely fashion."

The delay comes as Ankara has been at odds with its Western allies over the conflict in Gaza, while its tough diplomacy over the war in Ukraine has also irked some allies. Ankara maintains good relations with Moscow and Kyiv, opposing Russia's invasion but also the Western sanctions on Russia.

While NATO member Hungary has also not ratified Sweden's membership, Turkey is seen as the main roadblock to Sweden's accession.

Later on Thursday, the U.S. ambassador to Hungary said he had been assured by the Hungarian government that Budapest would not be the last to ratify Sweden's bid, adding he was "confident" Stockholm would soon be a NATO member.