Finland said on Monday that more Russians entered the country over the weekend than in any other this year so far after Moscow's military call-up announcement caused a surge in arrivals.
"Last weekend was the busiest weekend of the year for traffic on the eastern border," Mert Sasioglu of the Finnish border guard told AFP.
The border agency said nearly 8,600 Russians entered Finland via the land border on Saturday and nearly 4,200 crossed the other way.
On Sunday, more than 8,300 Russians arrived and nearly 5,100 left.
"The arrival rate is about double what it was a week ago," Sasioglu said.
"The main reason is the mobilization but it is also partly explained by the fact that both Finland and Russia eased Covid-19 restrictions during the summer."
Neighbouring Norway, which is not a member of the European Union but is in the Schengen area, also reported a slight increase in crossings from Russia at its Storskog border crossing in the far north.
On Sunday, 243 people entered Norway from Russia, of which 167 had Schengen visas, while 91 left for Russia, according to Norwegian police.
The police also stressed that these figures are still lower than the number seen before Covid, but said they expect a possible further increase this week.
Other countries, such as Georgia and Turkey, have also reported increased Russian entries in recent days.
Finland announced on Sept. 23 it planned to "significantly restrict the entry of Russian citizens" and would finalize the decision in the "coming days."
While the restriction is not yet in force, the border guard service said it was ready to apply the new rules "within a day."
Sasioglu said it was preparing for "difficult developments" as the situation evolved.
"It is possible that when travel is restricted, attempts at illegal border crossings will increase," he explained.
On Saturday, border guards caught four individuals suspected of crossing the border illegally in the Kuusamo region of eastern Finland. They immediately applied for asylum when detained.