Moscow [Russia]: Former NATO Secretary-General Anders Fogh Rasmussen says that the time for Sweden and Finland to join the military alliance is now, while Russian President Vladimir Putin is “preoccupied” with Ukraine.

“As far as Finland and Sweden are concerned, I think there’s a window of opportunity for [the] two countries to join, exactly now because Putin is preoccupied elsewhere. He can’t do anything about it,” Rasmussen told CNBC on Saturday.

He warned that it could take “months” for the accession procedures to be completed since the parliaments of NATO’s 30 member-states will all need to ratify the accession protocol.

“It will take some months and during that period both Finland and Sweden could potentially be exposed to Russian intimidation or even threats, and that’s why we have to guarantee their security,” Rasmussen said, “as if they were already members of NATO.”

Finland and Sweden started discussing the possibility of abandoning long-term neutrality and joining NATO amid the Russian military operation in Ukraine. The head of the alliance, Jens Stoltenberg, said in March that NATO would gladly welcome Finland and Sweden and could fast-track their membership applications if they decided to join.

The US expects Sweden to present its formal application to become a full member of NATO by the end of June, while Finland could decide on accession already this month.