Sweden is to join Nato after Hungary's parliament approved the Scandinavian country's application.
Hungary's vote ended months of delays to complete Sweden's security policy shift and followed a visit by Swedish Prime Minister Ulf Kristersson, during which the two countries signed an arms deal.
Sweden's NATO membership was supported by 188 lawmakers in the Hungarian parliament, with six against and no abstentions.
Hungarian Prime Minister Viktor Orban's government has faced pressure from Nato allies to fall in line and seal Sweden's accession to the alliance. Hungary was the last among the 31 members of Nato to clear the way for Sweden to join the Western defence alliance as war rages in Ukraine.
Swedish Prime Minister Ulf Kristersson, Hungarian Prime Minister Viktor Orban and Hungarian Parliament
Reuters
NATO's secretary general Jens Stoltenberg posted on social media: "Now that all Allies have approved, Sweden will become the 32nd Nato Ally. Sweden's membership will make us all stronger and safer,"
PM Kristersson said on social media: "Today is a historic day...Sweden stands ready to shoulder its responsibility for Euro-Atlantic security."
Stockholm abandoned its non-alignment policy for greater safety within the North Atlantic Treaty Organisation in the wake of Russia's invasion of Ukraine in 2022.
With Sweden following Finland into Nato, Western leaders said Russian President Vladimir Putin has effectively achieved the very thing he sought to avert when he launched his war in Ukraine, an expansion of the alliance.
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Hungarian Prime Minister Viktor Orban after the move was passedReutersSenior analyst at the Swedish Defence Research Agency Robert Dalsjo said: "Nato gains a member that is serious and capable and it removes a factor of uncertainty in Northern Europe.
"Sweden gains security in a crowd...supported by American nuclear deterrence."
While Finland became a NATO member last year, Sweden was kept waiting as Turkey and Hungary, which both maintain better relations with Russia than other members of the US-led alliance, raised objections.
Turkey withheld ratification on Sweden's membership demanding tougher action against militants from the Kurdistan Workers' party (PKK) it said had made a home in Sweden.
Sweden's Prime Minister Ulf Kristersson reacting to the news
Reuters/TT News Agency
Sweden changed its laws and relaxed rules over arms sales to assuage Turkey.
President Tayyip Erdogan also linked ratification with US approval of sales of F-16 fighter jets to Turkey, with Ankara now expecting the United States to work on securing the US Congress' endorsement.
The ratification will now be signed by the speaker of parliament and Hungary's president within a few days, after which the remaining formalities, such as depositing accession documentation in Washington, are likely to be concluded swiftly.