Ukraine launched a sweeping long-range drone assault on multiple Russian air bases over the weekend, targeting dozens of strategic bombers in what President Volodymyr Zelensky called "an absolutely brilliant result" and "our most long-range operation." The strikes, part of an 18-month covert operation codenamed "Spiderweb," come on the eve of direct ceasefire talks between Kyiv and Moscow scheduled for Monday in Istanbul.

The Security Service of Ukraine (SBU) said the campaign damaged 41 strategic bombers deep inside Russian territory, including aircraft used for missile strikes on Ukrainian cities. Video footage published by the agency showed explosions and rising smoke at Russia's Belaya air base in the Irkutsk region, nearly 3,000 miles from Ukraine. Ukrainian officials said the attacks inflicted more than $2 billion in estimated damages.

"Enemy strategic bombers are burning en masse in Russia," a Ukrainian intelligence source told NBC News. The operation was reportedly led by SBU chief Vasyl Maliuk and supervised by Zelensky himself. A Ukrainian official told Axios the drones were concealed beneath wooden cabin roofs installed on trucks, which were smuggled into Russian territory over the course of more than a year.

Zelensky posted on X, "These are Ukrainian actions that will undoubtedly be in history books. We are doing everything to make Russia feel the need to end this war." He also revealed that Ukrainian intelligence had established an operational base near the Russian Federal Security Service (FSB) in Chelyabinsk Oblast, more than 2,000 kilometers from the border.

Russia's Ministry of Defense confirmed that air bases in five regions had come under attack but claimed that most strikes were repelled. Authorities acknowledged aircraft fires in the Murmansk and Irkutsk regions but said they had been extinguished with no reported casualties.

The attack follows a night of Russian drone bombardments across Ukrainian cities. Kyiv's air force said Russia launched 472 drones in one of its largest overnight strikes in months. Earlier Sunday, a Russian missile strike on a Ukrainian army training site killed at least 12 soldiers and wounded 60 more, Ukrainian military officials said.

In a separate development, two railway bridges collapsed Saturday in Russian border regions. Officials in Bryansk and Kursk blamed sabotage for the incidents, which left seven people dead and dozens injured. Ukraine has not commented on the bridge collapses.

The dramatic escalation precedes ceasefire negotiations between Russia and Ukraine set to take place in Istanbul. Zelensky said the top priorities at the talks will include "a full and unconditional ceasefire, release of prisoners and the return of abducted children." He added, "The key issues can only be resolved by the leaders."

Secretary of State Marco Rubio spoke with Russian Foreign Minister Sergey Lavrov on Sunday and "reiterated President Trump's call for continued direct talks between Russia and Ukraine to achieve a lasting peace," State Department spokesperson Tammy Bruce said.