Ukraine's President Zelenskiy says intelligence shows Russia is preparing a massive new attack, Reuters reported.

He delivered the warning in Kyiv amid escalating cross-border strikes on energy infrastructure.

Ukrainian drone strikes have severely hit key Russian energy sites, the article says.

The Volgograd refinery shut down completely after a Ukrainian drone attack, Meduza reported citing Reuters.

Ukraine claims to have knocked out more than half of Russia's oil refining capacity, AP reported.

Russia has ramped up attacks on Kyiv's utility grid, testing air defenses and humanitarian resources.

The United States has made a fresh push for peace talks as the attack threat looms.

Read the full article on Zelenskiy's warning of a massive Russian attack.