The UK is looking to bolster Poland's air defences after suspected Russian drones were shot down in its airspace.
It is the first time a NATO country is known to have fired shots during Russia's war in Ukraine and raises concerns of a wider conflict.
In a bleak message, Polish Prime Minister Donald Tusk said it was "the closest we have been to open conflict since World War Two", but added that there was "no reason to believe we're on the brink of war".
Moscow denied responsibility for the incident, with the Russian defence ministry saying its drones had carried out a major attack on western Ukraine but it had not planned to hit any locations in Poland .
Image: Soldiers patrol the street after the alleged drone incursion into Poland. Pic: Reuters
What happened in Pola