The missile blast that killed two people appears to be an “unfortunate accident” and not an “intentional attack”, Poland’s president has said.
Andrzej Duda tweeted that officials had “no proof at the moment that it was a missile fired by the Russian side”.
He added: “There are many indications that it was an air defence missile, which unfortunately fell on Polish territory.”
On Wednesday morning, US President Joe Biden cast doubt on previous claims the missile, which hit a grain silo in Przewodow, was fired by Moscow.
Poland may trigger NATO Article 4 – Ukraine war latest
“There is preliminary information that contests that.
“I don’t want to say that until we completely investigate it, but it is unlikely in the lines of the trajectory that it was fired from Russia, but we’ll see.”
Polish prime minister Mateusz Morawiecki said his country was still looking at the possibility of launching the NATO Article 4 procedure, but it seemed it may not be necessary to use that measure.
NATO Secretary General Jens Stoltenberg said in a statement to media: “Yesterday’s explosion took place as Russia launched a massive wave of rocket attacks across Ukraine.
“An investigation into this incident is ongoing, and we need to await its outcome.
“But we have no indication this was the result of a deliberate attack and we have no indication Russia is preparing offensive military actions against NATO.
“Our preliminary analysis suggests that the incident was likely caused by Ukrainian air defence missile fired to defend Ukrainian territory against Russia cruise missile attacks.
“But let me be clear – this is not Ukraine’s fault. Russia bears ultimate responsibility as it continues its illegal war against Ukraine.”
Russia has insisted it did not fire the missile.
A spokesman for the defence ministry told Russia’s state-owned RIA news agency that its strikes on 15 November were no closer than 22 miles (35km) from the Polish border.
They claimed that images of the site showed the wreckage to be that of a Ukrainian S-300 missile.