Gov't spokesman: Poland to verify whether to launch NATO Article 4 consultations

The United States and Western allies said they were investigating but could not confirm a report on Tuesday that the blast in the village of Przewodów resulted from stray Russian missiles. Russia's defence ministry denied it.

"A moment ago we decided to verify whether there are grounds to launch procedures under Article 4 of the North Atlantic Treaty," Polish govermnment spokesman Piotr Mueller said after an emergency meeting.

Article 4 allows NATO members to bring any issue of concern, especially regarding security, for discussion at the North Atlantic Council.

Muller also said Poland was increasing the readiness of some military units, but declined to take any question including about the cause of the incident.

"We started procedures that are meant for such a situation, including, what have just been decided a moment ago, an increased readiness of some military units in Poland and increased readiness of other uniformed services in our country," he told reporters.

Polish President Andrzej Duda spoke to his U.S. counterpart Joe Biden, NATO chief Jens Stoltenberg, and Ukrainian President Volodymyr Zelenskiy after an explosion near the Ukrainian border killed two Polish citizens.

"Polish President Andrzej Duda finished a conversation with NATO Secretary-General (Jens Stoltenberg) just now," the head of Poland's National Security Bureau, Jacek Siewiera, said before announcing Duda was speaking with Biden. "As you know, we are verifying grounds to use Article 4 (of the NATO military alliance treaty) which means the consultations of all alliance members regarding the right answer. We are in close contact with our allies, with our key allies."

NATO ambassadors will meet on Wednesday at the request of Poland on basis of the alliance's Article 4, after an explosion in Poland close to the Ukrainian border reportedly caused by a stray Russian missile.

Members of the North Atlantic Treaty Organization (NATO) are committed to collective defense, so a Russian strike on Poland could risk widening the conflict between Russia and Ukraine, which began with Moscow's invasion in February.