WARSAW, Poland — Poland’s armed forces said today an unknown object entered the country’s airspace from the direction of Ukraine and subsequently vanished off radars.

The Operational Command of the Armed Forces said on social media platform X, formerly Twitter, that the unidentified object was observed by radars of Poland’s air defense system from the moment it crossed the border until the signal disappeared.

It said troops had been mobilized to identify and find the object. There were no immediate reports of any explosion or casualties.

Prime Minister Donald Tusk convened a meeting with the defense minister, military commanders and heads of national security bodies, to be followed by a meeting of the National Security Bureau. Tusk was also in contact with President Andrzej Duda, the supreme commander of Poland’s armed forces.

The governor of Lublin province in eastern Poland, Krzysztof Komorski, told the Onet news portal that the object appeared on radars near the town of Hrubieszow, where a border crossing with Ukraine is located. Komorski said he had no information to indicate it landed in Lublin province.

Poland’s border with Ukraine is also the European Union and NATO border with Ukraine.

On Friday, Ukrainian officials said Russia launched more than 100 missiles and dozens of drones against Ukrainian targets overnight in what an air force official called the biggest aerial barrage since Russia’s full-scale invasion of Ukraine in February 2022.

It was not clear whether the unidentified object that Poland reported was related to the barrage.

This is not the first time an unauthorized object has entered Poland’s airspace from the direction of Ukraine since Russia’s full-scale invasion. In November 2022, two men were killed when a missile struck the village of Przewodow, a few kilometers from the border. Western officials said they believed a Ukrainian air defense missile went astray.