The remains of an unidentified military object were found in a forest near Bydgoszcz in northern Poland, the country's defense ministry reported on April 27.
According to Polish radio station RMF FM, those are debris of an air-to-surface missile possibly belonging to the Polish army.
The police, military, and sappers are investigating the site, the defense ministry said, adding that the situation does not threaten the residents' safety.
The alleged missile, "several meters long" and missing a warhead, was found on April 24, but it's unclear when it had fallen and whether it had exploded, the RMF FM wrote.
Inscriptions in Russian were found on the wreckage, the journalists added. However, it doesn't necessarily mean that the military object is Russian as Poland has many post-Soviet weapons with Cyrillic inscriptions in its stocks, General Roman Polko, former commander of GROM Polish special forces, told the radio station.
"It did not necessarily come from Russia or the front line (in Ukraine). It should be remembered that we have MiG-29 (fighter jets) equipped with missiles," said Polko. He suggested that a Polish or Ukrainian pilot could miss when firing at an object on a training ground or a rocket could fall off.
Polko called it "highly unlikely" that the missile was fired over Poland's eastern border. Polish prosecutors are investigating the case.
Bydgoszcz is located more than 500 kilometers from the Polish-Ukrainian border and over 200 kilometers from the Russian Kaliningrad region.
In November last year, during a massive nationwide Russian attack against Ukraine, an explosion killed two people in the Polish village of Przewodow, about six kilometers west of the Ukrainian border.
According to Jakub Kumoch, head of the Polish president's International Policy Bureau, the Polish-American investigation team found evidence it had been a Ukrainian air defense missile, which was used to shoot down a Russian rocket but missed the target and fell in Przewodow.