Nato secretary-general Jens Stoltenberg said that Finland and Sweden would be embraced with open arms should they decide to join the 30-nation military organisation and could become members quite quickly.
Mr Stoltenberg’s remarks came as public support in Finland and Sweden for Nato membership mounts in response to Russia’s war in Ukraine.
Media speculation in the two countries suggest the two might apply in mid-May.
“It’s their decision,” Mr Stoltenberg said.
“But if they decide to apply, Finland and Sweden will be warmly welcomed, and I expect that process to go quickly.”
He gave no precise time frame, but did say that the two could expect some protection should Russia try to intimidate them from the time their membership applications are made until they formally join.
Mr Stoltenberg said he is “confident that there are ways to bridge that interim period in a way which is good enough and works for both Finland and Sweden”.
Nato’s collective security guarantee ensures that all member countries must come to the aid of any ally under attack.
Mr Stoltenberg added that many Nato allies have now pledged and provided a total of at least eight billion US dollars in military support to Ukraine.