NATO chief Jens Stoltenberg reacted after a Russian missile was shot down on The Polish territory near the Ukrainian border.
While it has been confirmed that the unidentified object that fell on Polish territory was a missile, it remains to be verified whether it belonged to Russia or the Ukrainian army's defence system.
Russia launched a major missile and drone attack on several Ukrainian cities today, targeting civilian infrastructure and killing 19 civilians and injuring 132 others.
"I spoke with President Andrzej Duda about the missile incident in Poland. NATO stands in solidarity with our precious ally, is monitoring the situation and we will stay in touch after the facts are established. NATO remains vigilant," Stoltenberg said.