NATO Secretary General Jens Stoltenberg says there's no indication that Russia is preparing military action against NATO.
It comes after a rocket landed in Poland, and killed two people.
Speaking in the past few minutes after an emergency meeting of the North Atlantic Council, Mr Stoltenberg said it was most likely caused by a Ukrainian air defence missile:
"An investigation into this incident is ongoing, and we need to await its outcome. We have no indication that this was the result of a deliberate attack, and we have no indication that Russia is preparing offensive military actions against NATO."
