The Kremlin has threatened to retaliate if Finland starts banning Russian tourists following its invasion of Ukraine.
Moscow said it would “react very negatively” should its neighbour refuse Russian citizens entry after it emerged there was growing support for this in Finland, Russian news outlet Interfax reported.
Kremlin press secretary Dmitry Peskov said: “Russia would, of course, react very negatively to this.”
He added: “All such actions against Russian citizens would require countermeasures and a response. This should be understandable and expected.”
On Monday, a survey from Finnish news agency STT showed there was strong support from sections of parliament to stop tourist visas for Russians after the country invaded Ukraine on 24 February.
Finnish acting prime minister Aki Lindén added he agreed with tightening visas for Russian tourists, news outlet yle reported.
Christina Hietasaari, head of Visit Finland, said last month Russian tourists accounted for as much as 19% of all tourists.
She added there were concerns the country could lose €600m (£504m) a year due to the decrease in their numbers caused by issues from the war.
On 5 July, Nato's 30 allies signed an accession protocol for Finland and Sweden, allowing them to join.
The protocol means Helsinki and Stockholm can participate in Nato meetings and have greater access to intelligence but will not be protected by the defence clause – that an attack on one ally is an attack against all – until ratification.
That is likely to take up to a year.
Moscow has repeatedly warned both countries against joining Nato.
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Finland's parliament also voted in favour of legislation allowing barriers on the country's border with Russia and enabling the closure of the 1,300 km (800 miles) frontier from asylum seekers in case of exceptional circumstances.
The bill on preparedness, while contested in terms of European Union asylum rules, was passed by a supermajority that allows parliament to fast-track laws, amid fears Russia could retaliate over Finland's plans to join the Nato military alliance.
It will also allow the government to decide to build fences or other barriers near Finnish borders and direct all asylum applications to one or several border crossings, such as an airport.