Finland's government declared a “new era” is underway as it inches closer to seeking NATO membership, hours before Sweden's governing party overnight backed a plan to join the trans-Atlantic alliance amid Russia's war in Ukraine.

Russia has long bristled about NATO moving closer to its borders, so the developments will be sure to further anger Moscow. President Vladimir Putin has already warned his Finnish counterpart on Sunday that relations would be “negatively affected.”

NATO Secretary-General Jens Stoltenberg said overnight the process for Finland and Sweden to join could be very quick. He also didn't expect Turkey to hold up the process.

Speaking after top diplomats from the alliance’s 30 member states met in Berlin, Stoltenberg also expressed his hope that Ukraine could win the war as Russian military advances appear to be faltering.

In Finland, President Sauli Niinisto and Prime Minister Sanna Marin confirmed earlier statements that their country would seek membership in NATO during a joint news conference at the Presidential Palace in Helsinki. The Nordic country, which was nonaligned before changing its stance on NATO, shares a long border with Russia.

“This is a historic day. A new era begins,” Niinisto said.

The Finnish Parliament is expected to endorse the decision in the coming days. A formal membership application will then be submitted to NATO headquarters in Brussels, most likely at some point next week.

Sweden, also nonaligned, moved a step closer to applying for NATO membership after the governing Social Democratic party met overmnight and backed joining the trans-Atlantic alliance.

The plan to join the alliance will be discussed in Sweden’s parliament on Monday (local time), and Prime Minister Magdalena Andersson’s Cabinet will make an announcement later that day.

The decision by the Social Democrats breaks with the party’s long-standing position that Sweden must remain nonaligned and means there’s a clear majority for NATO membership in Parliament.

Sweden has not been a member of a military alliance since the Napoleonic Wars. Finland adopted neutrality after being defeated by the Red Army in World War II and losing about 10% of its territory.

“Our 200-year-long standing policy of military nonalignment has served Sweden well,” Andersson said during a news conference in Stockholm late Sunday. “But the issue at hand is whether military nonalignment will keep serving us well?”

“We’re now facing a fundamentally changed security environment in Europe.”

Finland and Sweden abandoned traditional neutrality by joining the European Union in 1995.

Public opinion in both countries was firmly against joining NATO until the Russian invasion on Ukraine on Feb. 24, when support for membership surged almost overnight, first in Finland and later in Sweden.

NATO's secretary-general, meanwhile, sought to highlight Russian military setbacks.

“Russia’s war in Ukraine is not going as Moscow had planned,” Stoltenberg said by video link to the NATO meeting in Berlin as he recovers from a Covid-19 infection." “They failed to take Kyiv. They are pulling back from around Kharkiv. Their major offensive in Donbas has stalled. Russia is not achieving its strategic objectives.”

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“Ukraine can win this war," he said, adding that NATO must continue to step up its military support to the country.

The ex-Soviet republic of Georgia's bid to join NATO is again being discussed despite dire warnings from Moscow about the consequences. Both countries fought a brief war in 2008 over Georgia's breakaway region of South Ossetia.

Nordic NATO member Norway said it strongly welcomed Finland’s decision to seek membership. Norwegian Foreign Minister Anniken Huitfeldt described Helsinki’s move as “a turning point” for the Nordic region's defense and security policies.

Stoltenberg said he was confident the accession process for Finland and Sweden could be expedited. In the meantime, the alliance would increase its presence in the Baltic region to deter Russian threats, he said.

“All allies realise the historic magnitude of the moment,” Stoltenberg added.

That sentiment was echoed by German Foreign Minister Annalena Baerbock.

“Sweden and Finland, if you’re ready, we’re ready,” she said.

But NATO member Turkey has raised concerns about the two countries joining, alleging they support Kurdish militants that Ankara considers terrorists.

The Kurdistan Workers’ Party, or PKK, has waged an insurgency against Turkey since 1984 and the conflict has killed tens of thousands of people. Turkey has also been infuriated by US support for PKK-linked Syrian Kurdish militants to fight the Islamic State group.

Turkish Foreign Minister Mevlüt Çavuşoğlu told reporters in Berlin that Finland and Sweden had also imposed restrictions on defence sales to Turkey that he called “unacceptable.”

“It’s not because we are against the expansion of NATO, but because we believe countries who support terror and follow such policies against us should not be NATO allies,” Çavuşoğlu said.

Stoltenberg said his understanding is that Turkey wants to have its concerns over Finland and Sweden addressed first.

“Turkey has made it clear that their intention is not to block membership," he said.

Nonetheless, Turkey's raising of its grievances has led to concerns in Washington and Brussels that other NATO members might also use the admission process as a way to wring concessions from allies, possibly complicating and delaying accession.

US Secretary of State Antony Blinken, who spoke with Çavuşoğlu and will see him again on the margins of a special UN Security Council meeting later this week in New York, declined to comment on those concerns. But he was optimistic that all NATO members would support bids from Finland and Sweden.

“I’m very confident that we will reach consensus,” he said after the meeting in Berlin.