Sweden and Finland have confirmed they will apply for Nato membership in a historic shift that comes as a result of Russia's invasion of Ukraine.
In Sweden, the governing Social Democrats said they backed joining the Western security alliance, paving the way for the country to apply.
Russia sees Nato as a security threat and has warned of "consequences".
Sweden stayed neutral in World War II and for more than two centuries has avoided joining military alliances.
Finland shares a 1,300-km (810-mile) border with Russia. Until now, it has stayed out of Nato to avoid antagonising its eastern neighbour.
In a statement, Sweden's Social Democrats said they would "work toward" membership, something supported by the public and most opposition parties. A formal application is likely within days.
But the Social Democrats added that they were opposed to stationing nuclear weapons or hosting Nato bases.
"For us Social Democrats, it is clear that the military non-alignment has served Sweden well, but our conclusion is that it won't serve us as well in the future," she added.
She also said Sweden would be left in a "vulnerable position" if it was the only country in the Baltic region that was not a Nato member.
Finland's President Sauli Niinisto earlier confirmed his country would apply, calling it a "historic day".
He spoke to Russia's President Vladmir Putin about the decision, saying he wanted to "say it straight".
"I, or Finland, are not known to sneak around and quietly disappear behind a corner," he said.
Russia's president had previously told Finland it would be a "mistake" to join Nato, which was founded in 1949 to counter the threat from the Soviet Union.
President Putin mentioned Ukraine's intention to join the alliance as one of the reasons for the invasion.