Former prime minister Alexander Stubb, 55, on the centre right, and former foreign minister Pekka Haavisto, 65, from the green left, largely agree on Finland's foreign policy and security priorities.
The Ukrainian president's visit to Finland, one of only a few journeys he has made abroad since Russia's invasion last year, was announced only after his arrival amid tight security arrangements in the Finnish capital.
NATO requires the unanimous approval of its 30 existing members to expand, and Turkey and Hungary are the only countries that haven t yet ratified the Nordic duo s bids.