US President Joe Biden has said it is “unlikely” that a missile that killed two people in Poland on Tuesday was fired from Russia.
Russia has denied it was to blame for the missile that landed in Przewodow, on the Ukrainian border.
Poland said it was Russian-made, but US officials said initial findings indicated it was fired by Ukrainian air defences.
More than 90 Russian missiles were fired at Ukraine on Tuesday, Kyiv said.
Ukrainian President Volodymyr Zelensky said most of the rockets fired by Russian forces had been aimed at the country’s energy infrastructure.
Although the Ukrainian military said 77 were shot down, some of the missiles hit Lviv, not far from the country’s western border with Poland.
During the Russian attacks, two Polish workers were killed in a blast at a farm building in Przewodow, 6km (4 miles) from the border.
Nato member Poland’s military was placed on high alert, and Nato ambassadors were holding an emergency meeting in Brussels on Wednesday morning to assess their response. Poland was expected to invoke Article 4 of the Alliance’s treaty, which calls for consultations in the face of a security threat.
While Russia condemned as a “provocation” initial suggestions that it had fired the missile into Poland, President Biden told reporters at the G20 Summit in Bali that “preliminary information” contested those reports.
In a statement, Western leaders at the Bali summit condemned and civilian infrastructure and offered their full support to neighbouring Poland.
Among those attending were President Biden, UK Prime Minister Rishi Sunak, French President Emmanuel Macron and EU Commission President Ursula von der Leyen.
