Dozens of asylum seekers arrived at four Finnish border crossings with Russia on Friday, just hours before they were to close, a border guard captain told AFP.
Finland is to shut half of its eight crossings along its eastern land border with Russia from midnight (2200 GMT).
Authorities have accused Russia of seeking to destabilise Finland by letting undocumented migrants -- mainly from the Middle East and Africa -- cross into the Nordic country.
The surge has grown in recent weeks. "Most of them have come with bicycles. Today we have had about 60," said Jussi Vainkka, a border guard captain at the Nuijamaa checkpoint.
Russia had previously stopped irregular migrants getting to the border. "Maybe that’s the biggest change we have seen," Vainkka said.
Finland, which shares a 1,340-kilometre (830-mile) border with Russia, has seen increased numbers of asylum seekers since August, particularly nationals of Iraq, Somalia and Yemen.
"We have made preparations for many scenarios. Let’s see what will happen and we will react if it’s needed," Vainkka added.
On Thursday, Prime Minister Petteri Orpo said Russia was deliberately seeking to destabilise Finland in retaliation for it joining NATO this year.
He said there were "signs that entering Finland is being aided and encouraged" and the government was prepared for acts of "malice" by Russia.
European Commission president Ursula von der Leyen spoke to Orpo on Thursday and said that "Russia's instrumentalisation of migrants is shameful".
Moscow warned in April it would take "countermeasures... in tactical and strategic terms" after branding Finland's decision to join the Western military alliance an "assault" on its security.
Yasser Alu, an asylum seeker from Syria, told AFP he travelled to the Nuijamaa crossing point from Russia by bike, with others.
"I arrived in Moscow. After that I go to Saint Petersburg. After Saint Petersburg I go to the border here."
He said "someone from Russia helped us" and he had not had to pay to make the journey.
When the travellers arrived at the border, they had been met by a Finnish official.
"He asked us where you’re from and our names and took the passport."
Far from home, they are now waiting to see what the future holds.
The four southernmost crossing points with Russia -– Imatra, Niirala, Nuijamaa and Vaalimaa -- are to remain shut until February 18, 2024.
They are located in the most populated regions along the border.
Other asylum applications will be concentrated on two of the four remaining checkpoints, in rural areas further north.
Helsinki's ties with Moscow have deteriorated since Russia's invasion of Ukraine in February 2022. Finland abandoned decades of military non-alignment and join NATO amid concerns for its own security.