CNN Turk said a vote could be held as early as Tuesday while a source told AFP that it might be held on Thursday.

Turkey's ratification would leave Hungary as the last holdout in an accession process that Sweden and its neighbour Finland began in response to Russia's invasion of Ukraine nearly two years ago.

Finland became the 31st member of the US-led defence alliance last April.

Its membership roughly doubled the length of NATO's border with Russia and substantially strengthened the defences of three tiny Baltic nations that joined the bloc following the Soviet Union's collapse.

Sweden and Finland pursued a policy of military non-alignment during the Cold War era confrontation between Moscow and Washington.

But Russia's invasion of its western neighbour set off Europe's biggest and most brutal land battle since World War II, upturning geopolitical calculations.

Turkish President Recep Tayyip Erdogan's resistance to Sweden's NATO accession reflected his more nuanced stance toward Moscow.

Turkey has profited from maintaining -- and even expanding -- trade with Russia, while at the same time supplying Ukraine with drones and other essential arms.

Erdogan has also been one of the few Western leaders to hold regular meetings and phone conversations with Russian President Vladimir Putin.

Turkish media reported that Putin could make his first wartime visit to Turkey next month.

- US fighter jets -

Erdogan's objections to Sweden's bid initially focused on Stockholm's perceived acceptance of Kurdish groups that Ankara views as "terrorist".

Sweden has responded by tightening its anti-terrorism legislation and tacking other security steps demanded by Erdogan.

The Turkish parliament's foreign affairs committee approved the Swedish bid last month.

But Erdogan has since made new demands, including a request for Washington to follow through on its pledge to deliver a batch of F-16 fighter jets for Turkey's ageing air force.

Erdogan last month discussed his demands by telephone with US President Joe Biden.

Washington officials argued that Turkey's request could win the required congressional approval if Sweden's NATO accession goes through -- a position reaffirmed by US Secretary of State Antony Blinken during a visit to Istanbul this month.

Some analysts additionally linked Turkey's continued delays to Erdogan's anger at Washington for its support of how Israel is pursuing its war against Hamas militants in the Gaza Strip.

Erdogan has turned into one of the Muslim world's harshest critics of the scale of death and destruction happening in Gaza, which was unleashed by the militants' unprecedented October 7 attack on Israel.