Russia's foreign ministry has announced plans to expel nine Finnish diplomats, a move believed to be a response to Finland expelling nine Russian embassy employees last month.
Russia also said it was withdrawing consent to the operation of the Finnish Consulate General in St Petersburg, a measure it said will go into effect on 1 October.
Finnish President Sauli Niinistö said on Thursday that he has discussed possible countermeasures with party chairs of the coalition government.
"The counterpart of St. Petersburg's consulate general is Russia's consulate general in Turku," Niinistö wrote on Twitter.
Prime Minister Petteri Orpo (NCP) echoed Niinistö's message of urgency to react to Russia's actions.
"We have to respond to this, that is quite clear," Orpo said, adding that Turku's consulate had indeed been brought up in the discussions.
Niinistö characterised Russia's actions as "tough and asymmetrical".
At the beginning of June, the Finnish Security Intelligence Service (Supo) said that the nine Russian diplomats that were being expelled had met the criteria for counter-espionage. The security agency said the embassy staff members' expulsions were in line with its counter-espionage objectives.
Ahead of Russia's decision on Thursday, Finland had 57 Finnish staff members at its diplomatic missions in Moscow and St. Petersburg.
Taneli Dobrowolski, a communications coordinator at the Finnish foreign ministry, told Yle that a reduction in diplomatic staff would likely have a negative impact on the missions' capacity.
"A reduction in the number of staff will naturally have a negative impact on the capacity of the missions. The missions will continue to operate normally within their resources and prioritise their statutory tasks," he said.
Pekka Haavisto (Green) who was Finland's foreign minister at the time, said that countermeasures were to be expected.