Ukrainian President Volodymyr Zelenskyy is visiting Poland after the two countries reached an agreement on a longstanding source of tensions between them: the exhumation of Polish victims of World War II-era massacres by Ukrainian nationalists.

Relations between the neighbours have been strained for decades by the World War II-era Volyn or Volhynia killings that took place between 1943 and 1945. #EuropeNews

The Russian missiles sought out targets from the Lviv region in western Ukraine near Poland to Kharkiv in northeast Ukraine bordering Russia. The state energy company Ukrenergo reported emergency power outages in six regions. It often shuts down production during attacks as a precaution.

Russia's military on Tuesday said it would retaliate against Ukraine after Kyiv attacked Russian regions by firing six U.S.-made ATACMS ballistic missiles, six UK-made Storm Shadow cruise missiles and launching one of the biggest drone attacks to date.

NATO member Poland scrambled fighter jets after overnight Russian missile and drone attacks on Ukraine, Warsaw's military said on Wednesday. A spokesperson for the Operational Command of the Polish Armed Forces told Newsweek that "intense long-range aviation activity" from Russia had been detected early on Wednesday.