Ukraine’s spectacular Operation Spiderweb on June 1 destroyed fewer Russian strategic bombers than Kyiv first claimed, according to satellite evidence released by the US firm Maxar.

The Ukrainian Security Service (SBU), which planned and executed the sophisticated operation that targeted five airfields deep inside Russian territory, initially claimed that it had destroyed 41 strategic bombers that make up a third of its nuclear weapon delivery systems.

US officials said the damage was less, with some 20 Russian warplanes hit, but only 10-11 of them were destroyed, two US officials told Reuters.

The attacks damaged about a dozen aircraft which are expected to take years to restore, Ukrainian President Volodymyr Zelenskiy said in a video message. The strikes targeted four key airfields—Olenya, Ivanovo, Dyagilevo, and Belaya— deep in Russia’s interior used by Russian strategic aviation to bomb Ukrainian cities.

The assessment was backed up after the satellite firm Maxar released high quality images of the airfields that were attacked showing the damaged planes.

Nevertheless, the US officials described the attack as “highly significant,” and it has been a major PR and psychological victory for Bankova at a time when morale in the Armed Forces of Ukraine (AFU) is low as it faces an ongoing onslaught by Russian forces.

One of the officials cautioned that the attack could drive Moscow to a far more severe negotiating position in the US-brokered talks to end more than three years of war.

On the same day Russian President Vladimir Putin said that Russia would respond to what the Kremlin is calling a “terrorist” attack and questioned the need for a ceasefire that would only allow Ukraine to rearm.

“Why should we give them a pause and the opportunity to rearm with Western weapons?” Putin said in televised remarks.

"The current Kyiv regime does not need peace at all," Putin said at a meeting with senior officials concerning a new attack on the Kerch bridge on June 3 by the SBU shortly after the drone attack on airfields. "What is there to talk about? How can we negotiate with those who rely on terror?"

Russian Deputy Foreign Minister Sergei Ryabkov said separately that if these sort of attacks continue, the Kremlin would regard the West as being complicit.

Kyiv did not inform the US about the attack ahead of time and Zelenskiy said the attack would not have happened if Russia had agreed to a ceasefire.

US President Donald Trump held an hour-long phone call with Putin on June 4, which Trump described as a "good conversation, but not a conversation that will lead to immediate peace."

"President Putin did say, and very strongly, that he will have to respond to the recent attack on the airfields," Trump said, adding that he had urged restraint.

Trump's Special Envoy for Ukraine, Keith Kellogg, warned that Operation Spiderweb could lead to an escalation in the war and makes a ceasefire deal more difficult to do.

"I'm telling you the risk levels are going way up," Kellogg told Fox News on June 3 as cited by The Kyiv Independent. "When you attack an opponent's part of their national survival system, which is their nuclear triad, that means your risk level goes up because you don't know what the other side's going to do."

Trump has been largely silent on the Ukrainian attacks on the Russian bombers, one of the three pillars of Russia's nuclear arsenal. Russia and the United States together account for 88% of all nuclear weapons. Each has three ways of nuclear attack - strategic bombers, land-launched intercontinental ballistic missiles and submarine-launched ballistic missiles - and any attack on any part of the "triad" is considered a grave escalation, Reuters reports.