NATO: Sweden officially becomes alliance's newest member in moment hailed as 'historic' by Rishi Sunak
Rishi Sunak and Joe Biden have welcomed Sweden officially joining NATO, with the prime minister calling it a "historic moment".
Mr Sunak said the Swedish membership, along with Finland's a few months ago, will make the alliance stronger and "the whole euro-Atlantic" more secure.
He also said NATO has "never been more important than it is today" amid Russia's threats and "their barbaric war in Ukraine".
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US President Biden also congratulated Sweden on its admission and said it was a sign the Kremlin's intervention in Ukraine had united, rather than divided, the alliance.
Sweden becomes the 32nd member and its formal admission comes nearly two years after applying.
The Nordic country - which has not been at war since 1814 - has historically avoided military alliances for more than 200 years, and at the start of 2022 still ruled out joining NATO.
But after Russia's full-scale invasion in February that year, Sweden changed course and filed a joint bid with Finland to enter the organisation.
Mr Biden said in a statement on Thursday: "When Putin launched his brutal war of aggression against the people of Ukraine, he thought he could weaken Europe and divide NATO.
"With the addition of Sweden today, NATO stands more united, determined, and dynamic than ever - now 32 nations strong."
The US secretary of state, Antony Blinken, said at a ceremony in Washington to mark Sweden's entry into the alliance that "good things come to those who wait".
He received Sweden's accession documents from the country's prime minister, Ulf Kristersson.
Mr Kristersson said on his visit to the US: "Today is truly a historic day.
"We are humbled, but we are also proud. We will live up to high expectations from all NATO allies. United we stand. Unity and solidarity will be Sweden's guiding light as a NATO member."
Last month, Hungary's parliament voted to ratify Sweden's bid, which had been the last obstacle to it joining the transatlantic organisation.
All NATO members must agree to invite a country for it to join the alliance. After this, each member must sign and ratify the Accession Protocol for a country to formally join.
Helsinki's bid was approved by Budapest in March last year, with Finland officially becoming a NATO member the following month.
Budapest didn't give any clear reason for its refusal to back Sweden at first, and was believed to be following Turkey in demanding a series of conditions, including a tougher stance on Kurdish militants.
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Turkish President Recep Tayyip Erdogan had signed off on Sweden's membership in January, which left only Hungary to approve Stockholm's bid.
The full list of NATO members is Albania, Belgium, Bulgaria, Canada, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Italy, Latvia, Lithuania, Luxembourg, Montenegro, Netherlands, North Macedonia, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Turkey, the United Kingdom and the United States.