Germany's FGS Mecklenburg-Vorpommern and Portugal's frigate NRP Bartolomeu Dias will remain moored in Helsinki until Sunday, the Finnish Navy said.

Before docking in Helsinki, the ships took part in an exercise organised by the Finnish Coastal Fleet in the Gulf of Finland, together with three Finnish ships.

The navy said it was "the first time" that Finland and the Coastal Fleet had conducted an exercise since joining NATO.

Ending decades of military non-alignment, the Nordic country became the 31st member of NATO on April 4.

Finland and neighbouring Sweden announced bids to join NATO in May 2022, in the wake of Russia's invasion of Ukraine.

Hungary and Turkey are the last two NATO members yet to ratify Sweden's membership.

Finland's entry doubled the border between NATO countries and Russia, as Finland and Russia share a 1,340- kilometre (830-mile) border.

The former Soviet Union invaded Finland during World War II and even today the Nordic country of 5.5 million maintains mandatory military service that allows Helsinki to mobilise hundreds of thousands of reserves in the event of war.

Prior to formal membership, Finland regularly took part in NATO exercises in recent years as a member of the alliance's "Partnership for Peace".