Pakistan, Aug. 15 -- Ukrainian drones struck a major Russian oil refinery and an apartment block overnight, just hours before a high-profile summit between US President Donald Trump and Russian President Vladimir Putin in Alaska.

Military officials in Kyiv confirmed that the Syzran oil refinery in Russia's Samara region, a key facility in the Rosneft network producing aviation fuel for the Russian army, was successfully targeted.

Unverified images from the scene showed multiple fires and thick grey smoke rising from the refinery at dawn, signalling significant damage to the facility located about 800 kilometres from the front lines.

In a separate incident, a Ukrainian drone hit an apartment block in Russia's border region of Kursk, kil...