This article is from Tuesday. Click here for Wednesday's latest updates and reaction.
Two people died Tuesday afternoon after a projectile struck an area where grain was drying in Przewodów, a Polish village near the border with Ukraine, domestic media reported.
The Polish government raised its army's level of readiness after Prime Minister Mateusz Morawiecki called an emergency meeting of the country's top national security and defence officials due to a "crisis situation", according to government spokesman Piotr Mueller.
The government is also mulling whether to invoke NATO founding treaty's Article 4, calling for a meeting of all NATO Member States after an ally's territorial integrity or security has been breached.
Review Tuesday's developments as they happened in our blog below: