Finland said on Thursday it was considering barring most Russians from entering the country as traffic across the border from its eastern neighbour "intensified" following President Vladimir Putin's order for a partial military mobilisation.
Finnish land border crossings have remained among the few entry points into Europe for Russians after a string of Western countries shut both physical frontiers and their air space to Russian planes in response to Russia's invasion of Ukraine.
Prime Minister Sanna Marin said on Thursday the government was assessing risks posed by individuals travelling through Finland, and was considering ways to sharply reduce Russian transit.
"The government's will is very clear, we believe Russian tourism (to Finland) must be stopped, as well as transit through Finland," Marin told reporters.
"I believe the situation needs to be reassessed after yesterday's news," she added, referring to Putin's partial mobilisation order.
The Russian president's announcement raised fears that some men of fighting age would not be allowed to leave Russia and prompted one-way flights out of the country to sell out fast.
Finland opted to keep its frontier with Russia open following Moscow's Feb 24 invasion of Ukraine although it has cut back the number of consular appointments available to Russian travellers seeking visas.
At the Vaalimaa border crossing, roughly three hours' drive from Russia's second-largest city St Petersburg, three lanes of cars each stretched for 300-400 metres (yards) at around 1:15 pm local time (1015 GMT), a border official told Reuters.
The crossing is one of nine on Finland's 1,300-km (800-mile) border with Russia, the longest in the European Union.
"Traffic at the Finnish-Russian border intensified during the night," the border guard's head of international affairs, Matti Pitkaniitty, said in a tweet. He told Reuters that border guards were ready at the nine checkpoints.
Although traffic from Russia was busier than normal, the border guards said in a statement that it had not changed "alarmingly" in recent days compared with pre-pandemic times.
The statement warned that "incorrect and misleading" information was circulating on social media.
At around 1730 local time (1530 GMT), traffic continued to flow, according to a Reuters witness, with cars stretching over four lanes, each for some 150 metres.
A 34-year-old Russian man called Nikita, who did not give his last name, told Reuters he was going on holiday in southern Europe and said he was not sure if he would return to Russia.
"I will make the decision when I'm there," he said upon crossing the border.
Border officials told Reuters a significant amount of Russians arriving were travelling on tourist visas. Tourists must present visas and documents that prove their onward itineraries such as plane tickets, hotel bookings or an invitation from a friend.
As long as tourists can credibly show plans for return, such as return tickets, the border guards cannot check whether they actually plan to return, Elias Laine, the Vaalimaa border station's deputy chief, told Reuters.
Estonia, Latvia, Lithuania and Poland, the other EU countries that border Russian territory, began turning away Russian citizens from crossings at midnight on Monday, saying they should not travel while their country is at war with Ukraine.
The three Baltic nations will offer no refuge to any Russians fleeing Moscow's mobilisation of troops, their ministers said on Wednesday.
Pitkaniitty said 4,824 Russians arrived in Finland via the eastern border on Wednesday, up from 3,133 a week earlier.
In far northern Norway there had been no changes in the number of Russians crossing, a police official told Reuters. Norway is not a member of the EU.