Ukraine's President Volodymyr Zelenskyy congratulated Finland and its President Sauli Niinisto on joining the North Atlantic Alliance on Tuesday.

"Sincere congrats to Finland and President Niinisto on joining NATO on the 74th anniversary of its founding. NATO became the only effective security guarantee in the region amid Russian aggression," Zelenskyy underlined.

"We expect NATO Summit in Vilnius will bring Ukraine closer to our Euro-Atlantic goal," he added.

Sincere congrats to Finland & President @niinisto on joining NATO on the 74th anniversary of its founding. NATO became the only effective security guarantee in the region amid Russian aggression. We expect #NATOSummit in Vilnius will bring Ukraine closer to our Euro-Atlantic goal

— Володимир Зеленський (@ZelenskyyUa) April 4, 2023

Earlier, the President said that the Alliance summit should suggest further steps for Ukraine's membership (Ukr) - in particular, strategic security guarantees on its path to Euro-Atlantic integration.

On Tuesday, Finland officially became the 31st NATO member.

Finland's NATO accession will end the country's neutrality era. It was a non-aligned state throughout its independency gained in 1917. Finland was subjected to Soviet armed aggression in the early stages of World War II.

Russia's recent invasion of Ukraine has prompted the Finns to seek safety under NATO's collective defence agreement. Finland's accession roughly doubles the length of NATO's border with Russia.