Despite Turkish President Erdogan hinting that Turkey may admit Finland but not Sweden into NATO, Finland's former prime minister is optimistic.

- It is terribly important that we slow down and understand that we will jointly be NATO members in mid-July at the NATO summit in Vilnius, Lithuania, says Stubb.

On Thursday, Finland's Prime Minister Sanna Marin held a press conference with Sweden's Ulf Kristersson (M), where she confirmed that the countries' journey towards NATO is being done "hand in hand".

- I think it is important that we send a common message today.

Finland and Sweden applied together and it is in everyone's interest that we join NATO together, she said.