Expulsions of Russian intelligence officers and visa refusals have substantially weakened Moscow’s intelligence operations in neighbouring Finland in the past year, the Finnish Security and Intelligence Service said.

The intelligence agency, known by the abbreviation SUPO, said in a statement that Russian intelligence had been “squeezed” in the Nordic country because of the agency’s ability to compromise spy operations last year.

“The Russian intelligence station (in Finland) shrank to about half of its former size last year,” SUPO director Antti Pelttari said, adding that the main reasons for the decline were expulsions of suspected spies and visa refusals on the advice of his agency.

The falling number of intelligence officers and restrictions on travel across the border amid Moscow’s war in Ukraine have significantly undermined operating conditions for Russian spies in Finland, SUPO said.

It noted that operations under diplomatic cover have traditionally been the main instrument of Russian intelligence abroad, and Moscow was seeking to use, among other methods, cyber espionge to make up for the shortfall in human intelligence.

“While Russia is still seeking to station intelligence officers under diplomatic cover, it will have to find ways of compensating for the human intelligence shortfall, such as by increasingly adopting other forms of covert operation abroad,” Mr Pelttari said.

The agency said Russia, China and “certain other countries” were the most active users of intelligence operations to acquire information for their own ends and against the interests of Finland.

Finland, a nation of 5.5 million people, applied for Nato membership together with neighbouring Sweden in May.

It shares an 832-mile land border with Russia, the longest of any European Union member.

SUPO earlier said that Finland’s future Nato membership will make the Nordic country a more interesting target for Russian intelligence and influencing operations, and Moscow may seek to acquire Nato-related intelligence through its neighbour.