The United States believes that Russian President Vladimir Putin's threatened retaliation against Ukraine over its drone attack last weekend has not happened yet in earnest and is likely to be a significant,

Ukraine’s drone strike deep inside Russian territory left Kremlin officials angry and alarmed over the sudden vulnerability of a nuclear-capable air fleet far from the battlefield, according to people close to senior officials in Moscow.

"We counted on this project — 20,000 missiles. Anti-Shahed missiles. It was not expensive, but it's a special technology," President Volodymyr Zelensky said.

Days after Ukraine hit more than a third of multiple nuclear-capable bombers in Russia, Moscow launched a scathing attack on almost all of Ukraine, firing over 400 drones and 40 missiles. At least nine regions were affected with the missiles and drone attacks. They include Kyiv, Lviv, and Sumy.

High-resolution satellite images have emerged showing the destruction caused by Ukraine’s bold drone assault on five key Russian air bases

To upgrade its drones, Moscow has been adding SIM cards to transmit data back to Russia and updating anti-detection methods.

LIVE: Ukraine Destroys Russian Bomber Planes In Daring Drone Attack |Vantage with Palki Sharma Ukraine launched Operation Spiderweb - an unprecedented drone attack on Russia as part of which it targeted Moscow's bomber fleet - TU-95s and TU-22s.

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.