Mariusz Błaszczak, who is also Poland's defence minister, made the remark in an interview with public broadcaster Polish Radio on Thursday morning.
On Wednesday, private radio broadcaster RMF24 reported that Poland’s Internal Security Agency (ABW) had detained six people alleged to have been part of a Russian espionage ring spying on Poland’s rail lines, among other facilities, and possibly planning acts of sabotage.
The group was allegedly focusing its attention on weapons deliveries to Ukraine, according to news reports.
The Polish government said Interior Minister Mariusz Kamiński would make a statement on the matter at 11 a.m. on Thursday.
Błaszczak told Polish Radio: "I would like to emphasise the great success achieved by the officers of the ABW, because the whole spy network has been unravelled.”
He added: "This is undoubtedly proof that the Polish services work for the security of our country in a very efficient manner."
Asked if the spy ring may have posed a serious threat to Poland’s critical infrastructure, Błaszczak replied: “Of course. The threat was real."
He said more details would be provided by the interior minister during his news conference later in the day.
Poland busts Russian spy network
According to RMF24, the six people detained by Poland’s Internal Security Agency are from countries to the east of Poland and were working for Russian intelligence, the Reuters news agency reported.
The spies had hidden cameras on important railway routes, mainly in the southeastern Podkarpackie province, RMF24 said.
Some of the cameras were found close to Rzeszów-Jasionka Airport, now a key transfer point for weapons and ammunition being supplied to Ukraine.
Poland has stepped up security around key railway routes and critical infrastructure as a result of the discovery of the spy ring, according to RMF24.
Polish president, CIA chief meet in Warsaw
Meanwhile, Polish President Andrzej Duda met with the director of the United States’ Central Intelligence Agency (CIA), William Burns, in Warsaw on Wednesday, officials have announced.
The Polish presidential office said in a tweet that they discussed "the current security situation."
Thursday is day 386 of Russia’s war on Ukraine.
Source: IAR, Reuters, PAP, 300polityka.pl