Poland's State Protection Service (SOP) has neutralised a drone that was flying over sensitive government locations in Warsaw, Prime Minister Donald Tusk said in a post on X.
Two Belarusian citizens were detained in connection with the incident and police have launched an investigation into the incident, Tusk said.
The incident comes at a time of heightened regional tensions following a string of airspace violations.
Poland says its airspace was violated in the early hours of Wednesday by a record 19 drones, believed to be from Russia.
In response, the Armed Forces of Ukraine said it would send a team to Poland to provide anti-drone training.
The Polish government has traditionally been a staunch supporter of Ukraine's war effort.
Total support to Ukraine from Warsaw totals approximately €3.3 billion, in both military and humanitarian assistance.
Poland has also been one of the most welcoming countries in Europe for refugees from Ukraine since Russia's full-scale invasion in 2022.
The country currently hosts the most Ukrainian refugees of any country in Europe, believed to be somewhere in the region of 1 to 1.6 million, according to the UN Refugee Agency.
Faltering support
But as Moscow's war grinds on, anti-Ukrainian sentiment has been increasing, despite data showing that the influx of Ukrainians has brought benefits to Poland’s economy.
A study by Poland’s National Development Bank earlier this year showed Ukrainian refugees had paid more in taxes than they had received in benefits.
But a Flash Eurobarometer survey conducted last year found that support for people fleeing the war in Ukraine had a noticeably lower level of support in Poland, with around 60% of respondents favouring state support.
Meanwhile on Monday, Romania condemned what it called Moscow's "irresponsible actions" after a Russian drone allegedly entered Romanian airspace during an aerial attack on Ukraine.
That incident, on Saturday evening, prompted Bucharest to scramble fighter jets, the defence ministry said.
On Friday, NATO Secretary General Mark Rutte announced an "Eastern Sentry" programme which aims to deter further Russian incursions and show solidarity with Poland.
"We see drones violating our airspace. Whether it was intentional or not, it is unacceptable. The allies have expressed full solidarity with Poland. It is crucial to counter aggression and defend every member of the Alliance," Rutte said.
"The defence of the eastern flank is our key task. That is why we are launching the Eastern Sentry initiative to further strengthen our eastern flank."
