Russia has warned of "serious military and political repercussions" if Finland joins Nato amid the Ukraine crisis.
Russian Foreign Ministry spokesperson Maria Zakharova said the country's accession to Nato, the military alliance currently made up of 28 European countries plus the US and Canada, could "have detrimental consequences".
Following Russia's invasion of Ukraine this week, Finnish prime minister Sanna Marin said the debate surrounding Finland's membership of NATO "will change".
Asked about this on Friday, Zakharova began with a veiled warning.
In translated remarks at a press conference, she said: "The Finnish government's policy of military non-alliance is an important factor in ensuring security and stability in northern Europe.
"At the same time, we cannot help but note the targeted efforts of Nato and other members of this alliance to involve Finland as well as Sweden [a fellow non-member] in this alliance."
She said "the intensity of practical interaction between Helsinki and Stockholm with Nato" is "nothing new".
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She claimed "they have conducted NAato's military exercises - these countries have provided territory for such manoeuvres of this military alliance.
"We have seen this policy over a number of years... and Finland and Sweden should not base their security on damaging security of other countries. Their accession to Nato can have detrimental consequences... and face military and political consequences."
A follow-up tweet from the Russian Foreign Ministry read: "Finland’s accession to Nato would have serious military and political repercussions."
Prime minister Marin previously said last month it is "very unlikely" Finland - which borders Russia - would apply for a Nato membership during her current term of office.
"All in all, I believe the Nato discussion will increase in the coming years," she had told Reuters.
On Thursday, Nato secretary-general Jens Stoltenberg said that he "values the close partnership" with Finland and Sweden even if they are not members.
"This is a question of self-determination and the sovereign right to choose your own path and then potentially in the future, also to apply for Nato membership."
Putin’s invasion of Ukraine has seen Kyiv hit by air strikes, with fighting closing in on the capital.
Families were forced to hide in bomb shelters and subway stations as troops continued their assault in a bid to seize the city.
Tens of thousands of people have fled Ukraine's major cities to try and escape the fighting, with the UN warning on Friday that millions could be displaced.
Armed forces minister James Heappey told MPs that 194 Ukrainians, including 57 civilians, are confirmed to have died.
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