Dozens of Russian military aircraft have been destroyed in an unprecedented drone attack deep inside Russia, a Ukrainian official has said, the day before critical peace talks between Moscow and Kyiv resume in Istanbul.

It was already hard to imagine a breakthrough emerging from the direct talks between Russia and Ukraine set to be renewed in Istanbul on Monday.

The drone attacks came on the eve of expected peace talks in Istanbul between Russia and Ukraine, which were already strained by uncertainty and pressure from U.S. President Donald Trump.

There are at least five reasons why the attack amid the ongoing Russia-Ukraine war changes the rules of battlefield engagement

In an undisclosed location near the front line, Vanya, a Ukrainian soldier, traverses through a field covered in the traces of a deadly Russian weapon.

Two bridges have collapsed, causing trains to derail, in separate incidents within Russia, which Vladimir Putin's officials have blamed on "interference", a likely reference to Ukrainian saboteurs.At least seven people were killed and 30 suffered injuries after a bridge collapsed and a train derailed in Russia's Bryansk region that borders Ukraine,

The rapidly evolving drone technology on display in Ukraine shows the Western way of slow procurement isn't enough, the UK armed forces minister said.