In Eastern Ukraine, new Russian drone tactics have made supply roads nearly as dangerous as the trenches.

Ukraine has ramped up strikes on energy sites to increase pressure on Russia, which relies on revenue from oil and gas exports.

Long-range drones of the Security Service of Ukraine (SSU) and Special Operations Forces of the Armed Forces of Ukraine struck oil pumping stations on the Kuibyshev-Tikhoretsk pipeline in Russia's Volgograd and Samara oblasts on the night of Friday 19-20.

In the early hours of Saturday, September 20, Russia once again carried out a combined strike on Ukraine. Loud explosions were heard and continue to be reported in several cities. RBC-Ukraine outlines everything known so far about the overnight drone attack.

The challenge lies in the number of ground control systems, radars, and related components, some of which utilize artificial intelligence for precision targeting, Defense Minister Denys Shmyhal said.

"In my opinion, (the Russians) gave a signal... don't even think about providing Ukraine with additional air defenses. You may need to find a way to get it yourself," Zelensky said in an interview with Sky News.

Ukrainian forces are struggling to adapt to an elite Russian drone unit known as Rubicon that aims to bring cutting-edge technologies and tactics to the battlefield. New findings from RFE/RL’s Russian Services now shed more light on the secretive military unit.