A view shows damages after an explosion in Przewodow, a village in eastern Poland near the border with Ukraine, in this image obtained from social media by Reuters released on November 15, 2022. /via REUTERS

Polish government confirmed on Tuesday night that two Polish citizens were killed in explosions in the Polish city of Hrubieszow near the Poland-Ukraine border, amid media reports over missiles hit there in the afternoon.

“We are increasing the readiness of some military units and other uniformed services,” Polish government spokesman Piotr Muller said after a meeting at the National Security Bureau, which was urgently convened after the incident.

Poland is verifying whether there is ground to launch the procedures under Article 4 of the North Atlantic Treaty Organization (NATO), he added.

Article 4 of NATO’s founding treaty allows members to bring any issue of concern, especially related to the security of a member country, to the table for discussion within the North Atlantic Council.

The cause of the explosions has been unclear. TVP, TVN, among several mainstream Polish media outlets, said earlier that the blasts were reportedly caused by Russian rockets falling on eastern Poland, but no confirmed information has been given.

Russian Defense Ministry denied the reports by saying in a statement that “Polish mass media and officials commit deliberate provocation to escalate the situation with their statement on alleged impact of ‘Russian’ rockets at Przewodow.”

Russia has launched no strikes at the area near the Ukraine-Poland border, it said, adding that “the wreckage published by Polish mass media from the scene in Przewodow have no relation to Russian firepower.”

Polish President Andrzej Duda has spoken over the phone with U.S. President Joe Biden, NATO Secretary General Jens Stoltenberg, and Ukrainian President Volodymyr Zelensky, respectively on Tuesday evening, said Jakub Kumoch, head of the International Policy Bureau of the cabinet.

According to U.S. officials, initial findings suggested that the missile that hit Poland was fired by Ukrainian forces at an incoming Russian missile, the Associated Press reported, having earlier cited a senior U.S. intelligence official as saying the blast was due to Russian missiles.

After the incident, Hungarian Prime Minister Viktor Orban also convened the Defense Council Tuesday night and the Hungarian government was monitoring the developments, according to Hungarian media reports.