Finland announced tightened restrictions on travel from several countries on Wednesday, as the country stuck to its line of changing the rules based on coronavirus infection rates in other states.
The government's current policy is that border checks can be relaxed if a country records fewer than eight infections per 100,000 inhabitants in the past two weeks.
At a press conference on Wednesday, ministers said that this policy means that border checks will be reintroduced for travellers from Iceland, Greece, Malta, Germany, Norway and Denmark, even though all those countries are part of the Schengen travel area.
Countries outside Schengen that now face stepped-up checks are Cyprus, Ireland, San Marino and Japan.
Travellers arriving from those countries are asked to isolate themselves for two weeks, and travel to those countries is not recommended. The recommendation comes into force on Monday 24 August.
Those showing symptoms may be the subject of a quarantine order from an official, which are accompanied by the threat of prison time or fines if broken.
There will be no blanket mandatory quarantine orders based on travel history alone, according to the government.
Northern border communities may escape the quarantine recommendation, as the government said it would protect people living in those communities who need to cross the border to conduct their normal daily lives.
Interior Minister Maria Ohisalo (Green) said that in practice, that meant that people who showed proof they lived in communities near the Norwegian and Swedish borders could avoid lengthy checks and quarantine recommendations.
The government also said that flights from Skopje to Turku, which have brought in several coronavirus-infected patients in recent weeks, may be suspended if the Finnish Transport and Communications Agency (Traficom) recommends it.