The fire broke out in the Międzyleś area of Wołomin County, northeast of the Polish capital, and spread into state-managed forests in the Łochów and Mińsk forest districts, officials said.
More than 65 fire crews were deployed to the scene, supported by four Dromader firefighting aircraft, a police Black Hawk helicopter and specialised drone teams monitoring the blaze from the air.
Prime Minister Donald Tusk said he was in constant contact with the interior minister and emergency services chiefs as efforts to contain the fire continued.
"The most important priorities remain the safety of residents and bringing the situation under control," Tusk wrote on social media.
State Forests, the agency managing Poland's public forests, described the situation as dangerous, citing low humidity, high temperatures and gusting winds that were helping the fire spread.
Officials said the blaze had already consumed more than 10 hectares of forest, though firefighters cautioned that the affected area was likely much larger and had not yet been fully assessed.
Authorities ordered the evacuation of residents from two villages in the Stanisławów municipality as a precaution.
Police said officers were assisting with the evacuation and using public-address systems to provide instructions to local residents.
"We are ready to provide support at any moment," police spokesman Robert Opas told broadcaster Polsat News.
Fire service spokeswoman Karolina Jaworska said additional firefighting units from neighbouring counties had been dispatched, including two large firefighting task forces comprising dozens of firefighters and vehicles.
Photos: Polska Policja/x.com
No injuries had been reported as of Thursday evening.
The General Directorate for National Roads and Motorways said National Road 50 between Stanisławów and Łochów had been closed because of the fire, with traffic diverted onto regional and local roads.
A municipal crisis-management team was scheduled to meet later on Thursday to assess the situation and coordinate further response measures.
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Source: TVP Info, Polsat News, IAR, PAP, polskieradio24.pl