Russia denied on Monday accusations that it was sending migrants to the Finnish border, after Helsinki reported a surge in asylum seekers trying to get into its country illegally.

Finland shut four of its border crossings with Russia last week in response to the influx, accusing Moscow of trying to destabilise the country in retaliation for it joining NATO.

"We do not accept such accusations," Kremlin spokesman Dmitry Peskov told reporters on Monday.

"Border crossings are used by those who have the right to do so," he added, calling Finland's accusations "far-fetched".

Russia warned earlier that Finland could close all its border crossings.

"Such a decision would obviously contradict Finland's national interests," Deputy Foreign Minister Alexander Grushko told Russian news agencies.

Helsinki's ties with Moscow have deteriorated massively since Russia launched its assault on Ukraine last February.

In April, Finland abandoned decades of military non-alignment and joined the Western-led NATO military alliance, prompting Moscow to warn of "countermeasures".

Western countries had previously accused Russia's close ally Belarus of pushing tens of thousands of undocumented migrants across its border towards Poland and Lithuania in 2021 in retaliation for EU sanctions.